Wireless backup telephone device and associated support system

ABSTRACT

A wireless telephone backup device for landline telephone equipment that may be located on the customer side of the landline service connection, typically in a restricted access location, such as an attic, basement, or utility closet. An interconnection circuit in the backup device detects service interruptions in the subscriber&#39;s landline connection and, in response, powers on a wireless communication device to provide backup telephone service to the customer premises equipment. The interconnection circuit also provides the other features standard landline telephone service, including dial tone, ring voltage, and normal dialing for outgoing calls. The backup device also forwards incoming landline calls to the wireless unit in the backup device, and may send a message notifying a maintenance center of the service interruption. Further, the backup device may initiate an indicator in an alarm system at the site of the customer premises equipment to notify the subscriber of the service interruption.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/055,212, filed Jan. 22, 2002, now U.S. Pat. No. 6,757,528 which is acontinuation of U.S. application Ser. No. 09/268,591, filed Mar. 15,1999, now U.S. Pat. No. 6,411,802 issued Jun. 25, 2002, which isincorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to telecommunications systems,and relates more specifically to a device and system for providingwireless backup telephone service for landline telephone equipment.

BACKGROUND OF THE INVENTION

Telephone service in the North America is one of the most reliablecommunications systems in the world. The public switched telephonenetwork (PSTN), or landline network, uses copper and fiber opticland-based telephone lines as the standard for connecting end-usertelephone equipment to the network. Landline telephone equipment, knownin the art as customer premises equipment (CPE), receives and sendstelephone calls through the landline network. The reliability of thelandline network creates a consumer expectation of trouble-free,uninterrupted telephone service. Nevertheless, landline telephoneservice occasionally becomes interrupted, primarily due to damage causedto overhead landlines during severe weather.

For example, landline telephone service often becomes interrupted duringextreme weather events, such as hurricanes, floods, and ice storms.Because these weather events often coincide with electric power outagesand very difficult traveling conditions, many subscribers, such as theelderly, immobile persons, persons caring for young children, andpersons relying on home-based medical equipment may find that theseextreme weather events are the most important occasions to havetelephone service available. Emergency response personnel, privatecontractors specializing in tree removal, insurance adjusters,government officials, and utility personnel may also have an increasedneed to maintain telephone service during extreme weather events. Thoughno system can be guaranteed 100 percent reliable, these and othersubscribers may be willing to pay for any gain or increase inreliability of their telephone service.

In addition, when landline telephone service becomes interrupted, adelay in the repair time may occur if the service provider is notnotified as soon as possible. In some cases, the consumer may notrealize that his or her telephone service has been interrupted for anextended period, and the service provider will not be able to reactuntil the consumer notifies the service provider of the interruption.For example, if a subscriber's home telephone service becomesinterrupted while the subscriber is at work, the subscriber might notlearn of the interruption until returning home from work several hourslater.

Moreover, the telephone network is often relied on for security systems,such as burglar alarms, fire alarms, home-based medical monitoringsystems, home-arrest prisoner monitoring systems, and the like. In otherwords, the current landline telephone system serves as the communicationinfrastructure for a large part of the remote monitoring and securitysystems for businesses and homes by police, fire, emergency medicalpersonnel, and private security providers. For instance, many homeownersuse burglar alarms programmed to call the police or an alarm monitoringcompany when the alarm is triggered. These burglar alarms, in turn, usethe landline telephone system to communicate the alarm notifications tothe proper authorities. As a result, intentionally cutting the landlineproviding telephone service to the home defeats the notification featureof the alarm system.

One approach for solving the problems described above would be to issuea conventional wireless telephone to each landline subscriber. However,this approach would allow each subscriber to use both the landlineequipment and the wireless telephone at the same time. This type ofincrease in telephone service typically involves a monthly servicecharge that many subscribers may be unwilling to pay. In addition,assigning a second wireless directory number for each existing landlinedirectory number would consume a large number of directory numbers,which could deplete the number of available directory numbers in someareas. Alternatively, upgrading the telecommunications infrastructure toallow wireless telephones to use the same directory numbers as landlinetelephones on a large scale basis would require a significant investmentin the existing telecommunications infrastructure.

Thus, there is a need for devices to increase the reliability oflandline telephone service. In particular, there is a need for a devicecapable of backing up landline customer premises equipment duringlandline telephone service interruptions. There is a further need for atechnically and economically feasible mechanism for backing up landlinetelephone service without unnecessarily depleting the supply ofdirectory numbers or significantly increasing the existingtelecommunications infrastructure.

SUMMARY OF THE INVENTION

The present invention solves the problems described above in a wirelessbackup device that provides emergency backup telephone service tolandline telephone equipment. This backup device detects interruptionsin landline telephone service and automatically provides backuptelephone service to the landline telephone equipment through a wirelesstelephone. The backup device also notifies the telephone serviceprovider that the landline service has been interrupted, and may alsonotify the homeowner that telephone service has been interrupted, forexample through an indicator on an alarm panel. Because the backupdevice uses wireless communications, it provides backup service evenwhen the landline system is suffering widespread outages, such as duringextreme weather events. The backup device also increases the reliabilityof security and monitoring systems by providing an alternatecommunication system in cases of intentional landline telephone serviceinterruptions.

In addition, because the backup device operates only during veryinfrequent landline service outages, a large number of backup devicescan be supported by a relatively small number of temporary directorynumbers. That is, because a particular temporary directory number can beassigned to a backup device only while that device is in operation, andthen reassigned to another backup device at a later time, a large numberof backup devices can be installed without severely burdening the supplyof directory numbers. Similarly, because each backup device operatesvery infrequently, a telephone service provider can support a largenumber of backup devices without significantly increasing the existingtelecommunications infrastructure.

The backup device also provides an additional service that telephoneservice providers can offer as a value-added service to theirsubscribers. This may be a particularly important advantage in anenvironment of increased competition among telephone service providers.Because this type of backup service can be implemented without depletingthe supply of directory numbers or significantly increasing the existingtelecommunications infrastructure, it can be offered to subscribers at arelatively low cost. For example, it is expected that this type ofbackup service will be offered at a fraction of the cost of full-timewireless telephone service.

Generally described, the invention is a device and system for backing uplandline telephone service to customer premises equipment. The backupdevice detects interruptions in the landline service connection and, inresponse, powers on a wireless communication device. An interconnectioncircuit then functionally connects the customer premises equipment toreceive telephone service through the wireless device. Theinterconnection circuit also supplies traditional landline servicefeatures to the customer premises equipment, such as dial tone and ringvoltage. Once switched into connection with the customer-side of thelandline, the backup device provides what appears to be normal landlinevoice telephone service to all of the customer premises telephoneequipment. Specifically, the backup device provides all of the customerpremises equipment with ring voltage for incoming telephone calls, anddial tone with normal dialing for outgoing telephone calls.

To enable incoming as well as outgoing telephone calls, the backupdevice automatically forwards the landline telephone service to atemporary directory number assigned to the wireless device in the backupdevice. Specifically, the wireless device communicates through radiochannels with a mobile telephone switching office (MTSO) of a wirelesscommunication network. Upon powering on, the wireless deviceautomatically registers with the MTSO, obtains a temporary directorynumber from the MTSO, and transmits a forwarding message to forwardtelephone calls directed to the landline directory number to thetemporary directory number. This forwarding message is then relayed to atelephone redirection device, such as a switch servicing the landline ora local number portability platform (LNPP), to implement call forwardingfor the landline telephone service.

More specifically, bi-directional backup telephone service for thecustomer premises equipment is enabled as follows. For outgoingtelephone calls, someone in the premises dials a desired directorynumber from the customer premises equipment. The interconnection circuittransfers the directory number from the customer premises equipment tothe wireless communication device, which sends a call originationmessage containing the dialed directory number to the wireless network.The wireless network, in some cases in combination with the landlinetelephone system, then connects the outgoing telephone call to thecustomer premises equipment by way of the wireless device.

For incoming telephone calls, a calling party dials the subscriber'slandline directory number. Somewhere in the routing of the telephonecall to the landline, a telephone redirection device forwards thetelephone call to the temporary directory number assigned to wirelessunit in the backup device. This call forwarding feature routes thetelephone call to the MTSO where the wireless unit of the backup deviceis registered. The MTSO then connects the telephone call to the customerpremises equipment by way of the wireless device. The telephoneredirection device may typically be the switch that services thelandline for the customer premises equipment. Alternatively, thetelephone redirection device may be an LNPP that is typically consultedby the originating service switching point (SSP) for the incomingtelephone call.

The backup device also detects resumption of telephone service providedby the landline to the customer premises equipment. The interconnectioncircuit then disconnects the customer premises equipment from thewireless communication device, and powers down the wirelesscommunication device. The backup device may also transmit a messageinstructing a telephone call redirection device to unforward telephonecalls to the directory number assigned to the wireless communicationdevice to the directory number assigned to the customer premisestelephone equipment.

The backup device may be incorporated into a premises alarm system, suchas a home or business alarm. In this case, the backup device detectslandline interruptions to the customer premises equipment, providesbackup telephone service as described above, and also provides anindication of the landline interruption through the alarm system,typically by illuminating an indicator on an alarm panel. The alarmsystem may also implement other types of indications, such as adistinctive dial tone, distinctive ring, announcement, and the like. Inaddition, the alarm system may notify others of the landlineinterruption, for example by placing a telephone call or sending ane-mail to the telephone service provider, the police, an alarmmonitoring company, the homeowners' office telephone number, and soforth. Upon reactivation of landline service telephone service, thealarm system deactivates the landline interruption indicator, and mayalso notify others of the resumption of landline interruption.

Other objects, features, and advantages of the present invention willbecome apparent upon reading the following specification, when taken inconjunction with the drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the operating environment of the disclosedembodiments of the invention, specifically a backup device configured toprovide emergency wireless telephone service to a customer premisestelephone equipment.

FIG. 2 is a functional block diagram of the backup device configured toprovide emergency wireless telephone service to landline customerpremises equipment.

FIG. 3 is a functional block diagram with the components of a backupdevice in relation to elements of the public switched telephone network.

FIG. 4 is a functional block diagram of an interconnection circuit in abackup device connected to a wireless communication device.

FIG. 5 is a logic flow diagram of the operation of a backup device shownin FIG. 2.

FIG. 6 is a logic flow diagram of the operation of the telephone systemconnected to a backup device.

FIG. 7 is a logic flow diagram of a first type of failure analysissubroutine for the backup device shown in FIG. 2.

FIG. 8 is a logic flow diagram of a second type of failure analysissubroutine for the backup device shown in FIG. 2.

FIG. 9 is a logic flow diagram of a third type of failure analysissubroutine for the backup device shown in FIG. 2.

FIG. 10 is a logic flow diagram of a fourth type of failure analysissubroutine for the backup device shown in FIG. 2.

FIG. 11 is a logic flow diagram of a fifth type of failure analysissubroutine for the backup device shown in FIG. 2.

FIG. 12 is a logic flow diagram of a sixth type of failure analysissubroutine for the backup device shown in FIG. 2.

FIG. 13 is a logic flow diagram of a first method of call forwarding insupport of the backup device shown in FIG. 2.

FIG. 14 is a logic flow diagram of a second method of call forwarding insupport of the backup device shown in FIG. 2.

FIG. 15 is a logic flow diagram of a third method of call forwarding insupport of the backup device shown in FIG. 2.

FIG. 16 is a logic flow diagram of a fourth method of call forwarding insupport of a backup device.

FIG. 17 is a logic flow diagram of a fifth method of call forwarding insupport of a backup device.

FIG. 18 is a logic flow diagram of a sixth method of call forwarding insupport of a backup device.

FIG. 19 is a logic flow diagram of a seventh method of call forwardingin support of a backup device.

FIG. 20 is a logic flow diagram of an eighth method of call forwardingin support of a backup device.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention may be embodied in a backup device that is preferablylocated on the customer side of the landline service connection,typically in a restricted access location, such as an attic, basement,or utility closet. An interconnection circuit in the backup devicedetects service interruptions in the subscriber's landline connectionand, in response, powers on a wireless communication device to providebackup telephone service to the customer premises equipment. Theinterconnection circuit also provides the other features of standardlandline telephone service, including dial tone, ring voltage, andnormal dialing for outgoing calls. The backup device also forwardsincoming landline calls to the wireless unit in the backup device, andmay send a message notifying a maintenance center of the serviceinterruption. Further, the backup device may initiate an indicator in analarm system at the site of the customer premises equipment to notifythe subscriber of the service interruption.

The wireless communication network supports the backup device byreceiving the forwarding message from the wireless communication devicein the backup device. The wireless network then enters a forwardingrecord into a call redirection device to redirect calls to the directorynumber of the subscriber's landline connection to the wirelesscommunication device in the backup device. The call redirection devicemay be the switch that services the landline for the customer premisesequipment, or the call redirection device may be a local numberportability platform (LNPP). The landline network forwards incomingcalls to the customer premises equipment through the wireless network tothe wireless communication device. Outgoing calls are connected from thecustomer premises equipment to the wireless communication device. Thewireless device sends the outgoing calls over a radio frequency to thewireless network. The wireless network then routes the outgoing callsover the wireless and landline networks to deliver the calls to thecalled parties.

The present invention can be embodied in a self-contained enclosure thatconnects to standard telephone (e.g., RJ-11 telephone “in” and telephone“out”) and electric power (e.g., 120 Volt AC) outlets with an optionalconnection to an alarm system (e.g., twisted pair). The wireless devicewithin the enclosure may be implemented on circuit boards. Thisconfiguration may be advantageous because certain equipment in astandard wireless telephone is not required in the backup device, suchas a multifunction keypad, LCD, earphone, ringer, and microphone.Alternatively, an off-the-shelf wireless telephone may plug into socketswithin the enclosure. The enclosure is preferably locked and stored in arestricted access location to prevent inadvertent or intentionaltampering. By housing the backup device in a waterproof enclosure, thebackup device can easily be mounted inside or outside a customer's home.In this configuration, the backup device is a portable unit that can beeasily picked up from a retail store and carried to the customer's homeor office. The backup device can be easily unplugged for moving toanother location.

The enclosure incorporates a conventional modular plug connectionsupported by the casing of the enclosure to receive conventional modulartelephone jacks to connect the backup device to the telephone landlineconnection. That is, a customer can connect the backup device to thelandline connection by simply plugging conventional RJ-11 telephone “in”and telephone “out” jacks directly into the modular plugs located on thecasing of the enclosure. The enclosure also includes a conventionalelectrical power cord for connecting the backup device directly to aprimary power supply, such as the household 120 Volt AC system.

The components of the backup device typically include a wirelesscommunication device, an interconnection circuit, a microprocessor, anda power supply. A socket inside the enclosure holds the wirelesscommunication device in place. The wireless device can be removed fromthe socket for directory number programming or for maintenance orrepair. The power supply connects directly to the wireless device whenthe wireless device is placed directly into the socket. For example, abattery-charger combination can be used to power the wireless device byincorporating a rechargeable battery into the wireless device,connecting the wireless device to a compatible battery charger when thewireless device is in the socket, and powering the battery charger withan external household AC power supply.

The interconnection circuit functionally connects the wirelesscommunication device into the input wires of the customer's hometelephone. To supply standard landline features to the customer premisesequipment during a landline service interruption, the interconnectioncircuit includes a voltage generator, a ring generator, and a dial tonegenerator. That is, the interconnection circuit creates an apparentlyseamless communication connection between the customer's home telephoneand the wireless device of the backup device. When landline service isnon-functional, if a customer picks up the landline telephone, theinterconnection circuit creates a connection between the customerpremises equipment telephone and the wireless device, such that thecustomer can use the customer premises equipment to receive incomingcalls or to dial outgoing calls.

The microprocessor executes a line failure analysis routine to detectlandline failure conditions. In response to a landline failure, themicroprocessor activates the interconnection circuit according to theprogrammed line failure analysis routine in the microprocessor. Theinterconnection circuit controls the power supply and the wirelesscommunication device according to the programmed line failure analysisroutine in the microprocessor. The interconnection circuit utilizesconventional electrical components, detection devices, and circuitry.

A premises alarm system can also be connected to the backup devicethrough conventional connections incorporated in the casing of theenclosure. In response to a landline failure, the backup device can senda signal to the alarm system indicating that a landline failure existsand that local landline telephone service is non-functional. Thepremises alarm system includes an alarm indicator signal notifying thecustomer that the landline is out-of-service, and the backup device hasbeen activated.

Telecommunication service providers have already installed thetelecommunication equipment to support voice links between wirelesscommunication devices and the landline network. The landline networksupports the backup device by executing a call forwarding routine inresponse to receiving a message from a backup device indicating that alandline failure condition exists.

When the interconnection circuit of the backup device detects a landlinefailure condition, the interconnection circuit powers on the wirelesscommunication device. The wireless device sends a message to a localcellular serving switch connected to the landline network indicatingthat a landline failure condition exists. Upon receiving a message fromthe wireless device, the local cellular serving switch receives adirectory number for the wireless device. The local cellular servingswitch accesses a database to correlate the directory number for thewireless device with the landline directory number of the backup device.The local cellular serving switch sets a trigger in the switch servicingthe landline connection to the customer's home where the backup deviceis installed. The trigger contains call forwarding information to routeincoming calls directed to the landline directory number to thedirectory number assigned to the wireless device. That is, when acalling customer dials the landline directory number, the switchservicing that landline directory number routes the call to thedirectory number of the wireless device.

Thus, when a caller dials the landline directory number, the landlinenetwork can handle the call even though the landline connection to thatparticular landline directory number is out-of-service. A call for thelandline directory number received at the switch servicing the landlinedirectory number, routes the call to the directory number of thewireless device. The local cellular serving switch receives the call,and the local serving cellular switch sends the call over a radiofrequency to the wireless device. The wireless device receives the calland connects the call through the interconnection circuit of the backupdevice to the customer's landline telephone.

For outgoing calls from the landline directory number out-of-service,the interconnection circuit functionally connects the customer'slandline telephone equipment to the wireless device. The interconnectioncircuit collects the dialed digits of the outgoing call and sends thecomplete directory number through the wireless device to the localcellular serving switch. The local cellular serving switch routes thecall to the intended directory number in the landline network.

Customer premises equipment is also referred to as “terminatingequipment,” which can be telecommunications equipment including, but notlimited to, telephones, modems, facsimile machines, computers, orwireless telephones. Specific customer premises equipment, such as atelephone, can be referred to as “customer premises telephoneequipment.”

The wireless communication device may include any conventional analog ordigital wireless telephone or cellular radiotelephone. A suitablewireless communication device communicates with a wireless communicationnetwork functionally connected to the landline network. In addition, asuitable wireless communication device interfaces with the customerpremises equipment to permit voice and data transfer between thewireless device and the customer premises equipment. Such connectionsallow the wireless communication device to bypass the landline networkwhen service is interrupted, and to link the customer premises equipmentto the wireless communication network through the wireless communicationdevice.

Conventional registration methods for a wireless communication deviceoperating in a wireless communication network can be used to authorize,verify, and track the activities of a wireless communication device inthe wireless network. Other communication methods may be used totransfer voice or signal data from the subscriber's premises to a remotelocation, but suitable methods can transfer the voice or signal data toa remote location in the landline network.

Any conventional power source, without limitation, can be used to powerthe wireless communications device. A suitable power supply provides thewireless device with immediate and compatible power when the wirelessdevice is activated to receive or send a call on the wireless network.An example of a suitable power source is a sealed, portable lead acidbattery supplying direct current to the wireless device. Other powerdevices can be used, including a combination of a rechargeable batteryand battery charger connected to the conventional household alternatingcurrent (AC), or a direct connection from household AC to the wirelessdevice.

Service interruption conditions disable the ability of the customerpremises equipment to send outgoing or to receive incoming calls.Service interruptions can include physical severance of the connectionbetween the PSTN and the customer's premises, or an interruption causedby the failure of an electrical system supporting the PSTN including butnot limited to, loss of line current, loss of ring, loss of dial tone,and loss of line voltage.

Any type of call redirection device for redirecting telephone calls onthe landline communication network can be used. Suitable callredirection devices can be embodied in a single device or in a series ofdevices connected together to perform the same function. Examples ofcall redirection devices include, but are not limited to, the followingexamples: a series of connected switches linked to a home locationregister (HLR) database to direct a telephone call from one switch toanother, AIN (Advanced Intelligent Network) programming of a modifiedlocal network portability platform (LNPP) database working with inconjunction with programmable switches, a local number portabilityplatform (LNPP) linked to a local number portability (LNP) database in aservice control point (SCP), or any other conventional call forwardingmethods.

Any type of notification concerning the interruption of service or theactivation of the wireless backup device can be communicated to thecustomer and the telephone service provider. Suitable examples ofnotifying the customer and the telephone service provider include, butare not limited to, the following examples: a visual light on theterminating equipment, a unique dial tone emitted from the terminatingequipment when the telephone receiver is picked up, or a unique visual,audile, or tactile alarm relayed to the customer through an alarm panel.

Operating Environment of the Disclosed Embodiments

Referring now to the drawings, in which like numerals indicate likeelements throughout the several views, FIG. 1 is a functional blockdiagram illustrating the operating environment of disclosed embodimentsof the invention. The operating environment is specifically aconventional landline network 100 with a landline connection 101 to awireless backup telephone device 102 located on a customer premises 104.A customer premises equipment (CPE) telephone line 103 connects thebackup device 102 to customer premises equipment (CPE) 106.

The backup device 102 is generally connected to the landline connection101 between the customer premises equipment 106 and the public switchedtelephone network (PSTN) 108 of the landline network 100. The backupdevice 102 connects to the landline network 100 so that the backupdevice 102 detects landline telephone service interruption conditionsand monitors incoming and outgoing calls to and from the customerpremises equipment 106. In this example, the backup device 102 islocated at the customer premises 104, attached to the outside of thecustomer's home or business. The backup device 102 can be located at orremote to the customer premises 104 so long as the backup device 102monitors and detects service interruption conditions in the customer'slandline connection 101 to the landline network 100.

The backup device communicates through a radio frequency or channel witha mobile telephone switching office (MTSO) 110. The MTSO 110 interfaceswith the PSTN 108 through voice-channel lines. The MTSO 110 may be oneof several MTSO's comprising a wireless communication network linked tothe PSTN 108. The landline connections between the MTSO 110 and the PSTN108 facilitate communications between the wireless network and landlinetelephones operating in the PSTN 108. Thus, wireless communicationdevices operating on the wireless network can communicate withtelephones operating on the landline network.

The MTSO 110 connects to a home location register (HLR) 112. The HLR 112is a location register where user identities and other user informationcan be stored in and retrieved from a database of user records.Information such as directory numbers, user profiles, locations, andvalidation period can be stored in the HLR 112. The HLR 112 and the MTSO110 can be located at the same site or at remote points.

A series of service switching points (SSP's) 114, 116, commonly referredto as “switches” or “SSP's”, connect together in the landline network100 and connect to the PSTN 108. SSP's 114, 116 connect to the PSTN 108by voice-channel circuits and voice-channel lines. In the conventionallandline network 100, SSP's 114, 116 handle the forwarding, switching,and routing of landline network 100 telephone calls.

Typically, a directory number, commonly referred to as a “telephonenumber”, is assigned to each landline telephone connection serving acustomer premises. Several pieces of customer premises equipment 106 canbe connected to a single landline telephone connection 101, but all ofthe pieces of customer premises equipment linked to that single landlineconnection are assigned only one directory number. Multiple landlineconnections can be made to a customer premises, but each landlineconnection will have a different directory number.

A wireless communication device operating in a wireless communicationnetwork uses a directory number to identify the wireless device whilethe device is receiving or sending a call in the wireless network.Typically, only one directory number can be assigned to each wirelesscommunication device while the wireless device is sending or receiving acall. Various methods to assign a directory number to a wirelesscommunication device include, without limitation, the following:pre-assigning a directory number to the wireless device at the factory,assigning a virtual directory number or personal identification number(PIN), pre-assigning or pre-programming a mobile identification number(MIN), assigning a standard cellular directory number, or assigning atemporary directory number.

When a calling customer dials the directory number for the destinationcustomer premises equipment 106, an originating service switching point(SSP) 116 services the calling customer's telephone landline connection.The originating service switching point (SSP) 116 determines adestination switch to forward the call to by finding a terminatingservice switching point (SSP) 114 servicing the destination customer'slandline connection 101. A database in the SSP 114 cross-references thedialed directory number with a list of terminating service switchingpoints (SSP) to determine the correct destination switch for the call.The SSP 114 forwards the call through the PSTN 108 to the SSP 116servicing the destination customer's landline connection 101. The SSP116 routes the call with the dialed directory number to the landlineconnection 101 servicing the receiving customer premises equipment 106at the customer premises 104.

When more than one local telephone service provider in the samegeographic area installs and maintains switching equipment required toprovide telephone service, the conventional landline network 100 willrequire additional systems and methods to implement local numberportability (LNP). In an LNP-enabled network, the dialed directorynumber will not necessarily identify the correct terminating switch forthe call. It is anticipated that Advanced Intelligent Network (AN)upgrades in the conventional landline network will utilize a localnumber portability platform (LNPP) 118 to handle incoming calls. Aseries of LNPP platforms connected to a system-wide LNPP database orclearinghouse 118 will be directly linked to the PSTN 108 to implementlocal number portability.

The LNPP 118 will be a database or clearinghouse of ported directorynumbers and routing numbers for those ported directory numbers. Anyswitch in the PSTN will be able to access the LNPP 118 to routetelephone calls to the correct terminating switch using the routingnumbers obtained from the LNPP. This will allow originating switches toroute outgoing telephone calls using the most direct availablecommunication path from the originating service switching point (SSP) tothe terminating service switching point (SSP). To forward telephoneservice for the landline 101 in an LNP enabled network, the MTSO 110serving the backup device 102 assigns a temporary directory number tothe backup device. The MTSO 110 then enters the temporary directorynumber assigned to the backup device 102 as the routing number for thelandline 101 in the LNPP 118.

The SCP 120 is a remotely programmable intelligent network element,capable of maintaining and updating network databases through the use ofrelatively powerful computers. The SCP 120 may contain a local versionof the LNPP 118. In addition, the SCP 120 may be used to forwardtelephone service for the landline 101 in a non-LNP enabled network.Specifically, the MTSO 110 enters the temporary directory number intothe SCP 120 as a forwarding directory number for the landline 101. TheMTSO 110 also activates a trigger for the landline 101 at the SSP 116that services the landline. This trigger causes the SSP 116 to hold allincoming calls directed to the landline 101, and to consult the SCP 120for instructions. The SCP 120, in turn, instructs the SSP 116 to routethe call to the temporary directory number assigned to the backup device102. This causes the SSP 116 to route the call to the MTSO 110, whichroutes the call to the backup device 102. Upon reactivation of thelandline 101, the MTSO 110 deactivates the trigger for the landline 101in the SSP 116 and deletes the forwarding record for the landline in theSCP 120.

The backup device 102 also connects to an alarm system 122, which may belocated the customer premises or at a remote location. An alarmconnection connects the alarm system 122 to the backup device 102. Thealarm system 122 alerts the home or business owner or another systemmonitor of the failure of landline telephone service and the existenceof any landline failure conditions. The alarm system 122 may also notifyothers that landline telephone service has been interrupted, for exampleby automatically placing a telephone call or sending an e-mail to notifythe police or an alarm monitoring company that an emergency situationexists.

In FIG. 2, a backup device 102 connects to a landline connection 101 andto customer premises equipment 106. An enclosure 200 houses the backupdevice 102 facilitating easy installation and connection of the backupdevice 102 to the landline connection 101 and to the customer premisesequipment 106. For example, a telephone service provider can rapidlyinstall the backup device 102 by attaching the enclosure to the 200customer premises 104, and then connecting the backup device 102 to thelandline connection 101, to the customer premises equipment 106, and toan a/c power line 202. The enclosure 200 housing the backup device 102also protects the components of backup device 102 from the weather andfrom any intentional or inadvertent physical tampering.

The backup device 102 detects landline telephone service interruptionsto the customer premises 104. The backup device 102 detects serviceinterruptions using an interconnection circuit 204 that is connected tothe landline connection 101 and to the customer premises equipment 106.When a service interruption does occur, the customer cannot use thecustomer premises equipment 106 to receive calls, to send calls, or bothreceive and send calls to others in the public switched telephonenetwork 108. An example of an interconnection circuit 204 to detectfailure conditions is illustrated in FIG. 4.

Upon detecting a failure condition, the backup device 102 provideswireless telephone service to the customer premises 104 for a customerattempting to receive or to send a landline call on the PSTN 108. Thebackup device 102 initiates wireless telephone service by powering awireless communication device 206. The wireless device 206 attaches toan interior wall of the enclosure 200 through use of a socket 208. Thesocket 208 physically holds the wireless device 206 inside the enclosure200.

An alternating current (AC) power input 202 supplies conventionalhousehold electric AC to the interconnection circuit 204. Theinterconnection circuit 204 controls the supply of electric current to acharger 210 connected to the interconnection circuit 204. The charger210 is electrically and physically compatible with the wirelesscommunication device 206 to convert the electric current to a voltageand current necessary to power the wireless device 206. The wirelessdevice 206 operates through the supply of electrical current by thecharger 210.

The wireless communication device 206 communicates with a mobiletelephone switching office (MTSO) through a radio frequency. Thewireless communication device 206 functionally connects to the customerpremises equipment 106 through the interconnection circuit 204. Usingwell-known interface systems in the art, the wireless communicationdevice 206 receives dialed directory numbers from the customer premisesequipment 106, or transfers incoming wireless calls to the customerpremises equipment 106. These interface systems provide a relativelyseamless communication link between the customer premises equipment 106and the wireless communication device 206.

The interconnection circuit 204 connects to an alarm system 122 locatedbetween the customer premises equipment 106 and the PSTN 108. The alarmsystem 122 connects to a variety of status indicators or telephonebackup indication devices, including but not limited to, an alarm 212,an annunciator 214, or a control panel 216. Each of these examples issuitable for alerting the homeowner, a telephone service provider, or amaintenance center as to the existence of a service interruptioncondition in the landline connection 101 between the customer premisesequipment 106 and PSTN 108. Activation of the backup device 102 forinitiating wireless telephone service to the customer premises 104 sendsan automatic notification to the telephone service provider thatlandline service has been interrupted.

FIG. 3 is a functional block diagram illustrating the components of abackup device 102 in relation to elements of the landline network 100.As shown in FIGS. 1 and 2, the backup device 102 connects to thecustomer premises equipment 106, an alarm system 122, and the landlineconnection 101 to the PSTN 108. The microprocessor 302 of the backupdevice 102 executes a device routine to detect landline serviceinterruption conditions. When a detection device 304 in theinterconnection circuit 204 of the backup device 102 detects a landlineservice interruption, the microprocessor 302 powers on a wirelesscommunication device 206. The wireless device 206 is powered on byturning on a power supply 306 connected to the household electrical AC308 by an AC power connection 202. A switch 310 in the interconnectioncircuit 204 functionally connects the wireless device 206 to thecustomer premises equipment 106. The wireless device 206 sends a messagethrough a radio frequency or channel to a mobile telephone switchingoffice (MTSO) 110 to initiate a registration routine with the MTSO 110.

The MTSO 110 begins a subroutine to redirect telephone calls using atelephone call redirection device 312. The telephone call redirectiondevice 312 connects between the MTSO 110 and PSTN 108. A callredirection device 312 comprises a single device or several componentsfunctionally connected to cooperate together to forward and to switchcalls between the landline network 100 and the wireless network. Thecall redirection device 312 forwards incoming calls directed to thecustomer premises to the MTSO 110 serving the wireless communicationdevice 206 at the customer premises.

Turning now to FIG. 4, a functional block diagram of an interconnectioncircuit 204 in a backup device 102 is shown. The interconnection circuit204 connects to a wireless communication ,device 206 and charger 210,customer premises equipment 106, and a landline connection 101. Theinterconnection circuit 204 monitors the landline connection 101 betweenthe customer premises equipment 106 and the landline network 100 forservice interruption conditions.

A conventional landline connection 101 from a public switched telephonenetwork (PSTN) 108 to a customer premises 104 utilizes input wires 402.Typically, two wires commonly referred to as “tip” and “ring” are usedas the input wires 402. The input wires 402 are voice channel lines(shown as bold lines in FIG. 4) that connect the landline connection 101to a switch 310. A control line 404 connects a detection device 304 ofthe interconnection circuit 204 to the input wires 402 between thelandline connection 101 and the customer premises equipment 106. Acustomer premises equipment (CPE) telephone line connects the switch 310to the customer premises equipment 106. Typically, the CPE telephoneline 103 is a voice channel line.

When the backup device 102 is not activated, or when there is nolandline failure condition, the switch 310 connects the landlineconnection 101 through the input wires 402 to the customer premisesequipment 106 through the CPE telephone line 103.

When the backup device 102 is activated in response to a landlinefailure, the switch 310 connects the wireless communication device 206to the customer premises equipment 106 through the CPE telephone line103 and a voice channel line 103 between the switch 310 and the wirelessdevice 206. A control line 408 connects the switch 310 to themicroprocessor 302. The microprocessor 302 executes a line failureanalysis subroutine to determine landline failure conditions, andactivates the switch 310 in accordance with certain line failureconditions. A line failure analysis subroutine will be described inFIGS. 7–12 to further illustrate the functionality of theinterconnection circuit 204.

A control line 410 connects the microprocessor 302 to the detectiondevice 404. The detection device 304 connects to the landline connection101 through the input wires 402. The detection device 304 detects andmonitors service interruptions in the landline connection 101 andreconnections of landline service to the customer premises equipment106.

The detection device 304 incorporates several pieces of detectionequipment to monitor the input wires 402 from the landline connection101, and to monitor the CPE telephone line 103 to the customer premisesequipment 106 while the customer premises equipment 106 is on hook (thecustomer is not using the customer premises equipment 106) and off hook(the customer is using the customer premises equipment 106, attemptingto place or to receive a call). For example, different pieces ofdetection equipment in an interconnection circuit 304 can include,without limitation, a voltage detector 412, a ring detector 414, acurrent detector 416, a dial tone detector 418, a dual tonemulti-frequency (DTMF) receiver 420 or a dial PULSE decoder, a storagememory 422 or buffer, and a call progress monitor 424. Other similardetection equipment can be installed in the detection device 304 or theinterconnection circuit 204 depending upon the specific line failureanalysis to be performed on the landline connection 101 to detect or tomonitor landline service interruptions, and also depending upon the lineanalysis to be performed on the CPE telephone line 103 connecting to thecustomer premises equipment 106.

The voltage detector 412 detects voltage loss in the input wires 402from the landline connection 101. If a voltage loss is detected, thevoltage detector 412 sends a signal indicating a voltage loss. Thedetection device 304 sends the signal through the control line 410 tothe microprocessor 302 indicating a voltage loss. The microprocessor 302activates the switch 310 through control line 408 to functionallyconnect the wireless device 206 with the customer premises equipment 106through voice channel line 406.

Subsequently, the voltage detector 412 also detects when sufficientvoltage is restored in the landline connection 101. In response todetecting sufficient voltage in the landline connection, the voltagedetector 412 sends a signal indicating sufficient voltage. The detectiondevice 304 sends the signal through the control line 410 to themicroprocessor 302 indicating sufficient voltage. The microprocessor 302activates the switch 310 through control line 408 to functionallyconnect the landline connection 101 with the customer premises equipment106 through the input wires 402.

A ring detector 414 detects when a ring voltage has been generated onthe landline connection 101. In an insufficient ring voltage has beendetected, then the ring detector 414 sends a signal indicatinginsufficient ring voltage. The detection device 304 sends the signalthrough the control line 410 to the microprocessor 302 indicating a lossof ring voltage. The microprocessor 302 activates the switch 310 throughcontrol line 408 to functionally connect the wireless device 206 withthe customer premises equipment 106 through voice channel line 406.

The current detector 416 detects current loss in the landline connection101. If a current loss is detected, the current detector 416 sends asignal indicating a current loss. The detection device 304 sends thesignal to the microprocessor 302 through control line 410 indicating acurrent loss. The microprocessor 302 activates the switch 310 throughcontrol line 408 functionally connecting the wireless device 206 withthe customer premises equipment 106.

Subsequently, the current detector 416 also detects when sufficientcurrent is restored in the landline connection 101. In response todetecting sufficient current in the landline connection, the currentdetector 416 sends a signal indicating sufficient current. The detectiondevice 304 sends the signal through the control line 410 to themicroprocessor 302 indicating sufficient current. The microprocessor 302activates the switch 310 through control line 408 to functionallyconnect the landline connection 101 with the customer premises equipment106 through the input wires 402.

When the wireless device 206 is connected with the customer premisesequipment 106, the current detector 416 detects current in the CPEtelephone line 103 connecting the customer premises equipment 106 withthe wireless device 206. If the customer premises equipment 106 is offhook, the current detector 416 detects current, and the current detector416 sends a signal indicating that the customer premises equipment 106is off hook. The detection device 304 then sends the signal to themicroprocessor 302 through control line 410 indicating that the customerpremises equipment 106 is off hook.

If the customer premises equipment 106 is on hook, the current detector416 detects no current in the CPE telephone line 103, and the currentdetector 416 sends a signal indicating that the customer premisesequipment 106 is on hook. The detection device 304 then sends the signalto the microprocessor 302 through control line 410 indicating that thecustomer premises equipment 106 is on hook.

The dial tone detector 418 detects loss of dial tone in the landlineconnection 101. If a loss of dial tone is detected, the dial tonedetector 418 sends a signal indicating a loss of dial tone. Thedetection device 304 then sends the signal to the microprocessor 302through control line 410 indicating a loss of dial tone. Themicroprocessor 302 activates the switch 310 through control line 408,functionally connecting the wireless device 206 with the customerpremises equipment 106 through voice channel line 406.

Subsequently, the dial tone detector 418 also detects when a dial toneis restored in the landline connection 101. In response to detecting adial tone in the landline connection, the dial tone detector 418 sends asignal indicating a dial tone. The detection device 304 sends the signalthrough the control line 410 to the microprocessor 302 indicating a dialtone. The microprocessor 302 activates the switch 310 through controlline 408 to functionally connect the landline connection 101 with thecustomer premises equipment 106 through the input wires 402.

The voltage generator 428 generates a voltage on through voice channelline 430 to the CPE telephone line 103 for the customer premisesequipment 106. Thus, even though landline service has been interrupted,a caller from the customer premises equipment 106 will be able to pickup the phone to place or to receive a call. In general, if a callerattempts to place an outgoing call from the customer premises equipment106 when a landline interruption exists, the current detector 416detects current in the CPE telephone line 103 indicating the customerpremises equipment 106 is off hook. The current detector 416 sends asignal indicating that customer premises equipment 106 is off hook and acall attempt is being made. The detection device 304 sends the signal tothe microprocessor 302 through control line 410 indicating that customerpremises equipment 106 is off hook. The microprocessor 302 activates theswitch 310 through control line 408 to functionally connect the wirelessdevice 206 with the customer premises equipment 106 through the CPEtelephone line 103 and the voice channel line 406.

Next, the microprocessor 302 sends a signal through control line 432activating a dial tone generator 434 to generate a dial tone on thewireless device 206 through voice channel line 436 and to the CPEtelephone line 103. Thus, even though landline service has beeninterrupted, the caller will be able to pick up the phone and hear adial tone.

When the caller attempts to dial a directory number, the DTMF receiver420 or dial PULSE decoder collects the dialed digits of the directorynumber and stores the dialed digits in the storage memory 422 or bufferuntil a complete directory number has been dialed. When themicroprocessor 302 detects that a complete directory number has beendialed, the microprocessor 302 sends a signal through control line 438to the wireless device 206, and the wireless device 206 places the callover a radio frequency to a mobile telephone switching office (MTSO)110. The MTSO 110 connects the call over the landline network 100.

When the call is connected through the wireless device 206 to thelandline network 100, the call progress monitor 424 monitors the statusof the call. The call progress monitor 424 detects call progresssignals, such as a busy signal, a ringing signal, or a dial tone. Inresponse to detecting any of these conditions, the call progress monitor424 sends signal through the control line 410 updating themicroprocessor 302 as to the status of the outgoing call.

If an incoming call to the landline directory number is received by thelandline network 100, the landline network routes the call to the MTSO110 and sends the call over a radio frequency to the wireless device206. When the wireless device 206 receives the call, the wireless device206 sends a signal through the control line 438 to the microprocessor302 indicating that an incoming call has been received. The voltagegenerator 428 generates a voltage through the voice channel line 430 tothe CPE telephone line 103 and to the customer premises equipment 106.The microprocessor 302 sends a signal through control line 440activating a ring generator 442. The ring generator 442 generates aringing voltage through a voice channel line 444 to the CPE telephoneline 103 to generate a ring on the customer premises equipment 106. Whena customer answers the incoming call at the customer premises equipment106, the call is connected through the CPE telephone line 103 from thewireless device 206 to the customer premises equipment 106. Thus, evenwhen landline service has been interrupted, the customer at the customerpremises equipment 106 will hear a ring and be able to pick up the phoneto answer an incoming call.

In the absence of a landline failure condition, or when the landlineservice is restored, the switch 310 connects the landline connection 101through the input wires 402 to the customer premises equipment 106through the CPE telephone equipment 103. The microprocessor 302continues to monitor the detection equipment of the detection device 304through the control line 410 for landline interruption signals in thelandline connection 101 through the control line 404.

FIG. 5 illustrates a logic flow diagram of the operation of a backupdevice shown in FIG. 2. Prior to any landline service interruption to acustomer premises 104 operating a backup device 102 in a landlinenetwork 100, the microprocessor 302 initiates a device routine at startstep 500. Step 500 is followed by step 502, in which the interconnectioncircuit 204 initiates a line failure analysis subroutine to monitor thelandline connection 101 for service interruptions. When a detectiondevice 304 of the interconnection circuit 204 detects a failurecondition in step 502, the subroutine returns to step 502 and the deviceroutine continues in FIG. 5.

Step 502 is followed by step 504, where the microprocessor 302 of theinterconnection circuit 204 of the backup device 102 responds todetection of a failure condition by powering a wireless communicationdevice 206 in the backup device 102. After the wireless device 206activates, the wireless device 206 begins a registration subroutine inthe following step 506.

Step 504 is followed by step 506, in which the wireless communicationdevice 206 sends a registration message to a MTSO 110. When the wirelessdevice 206 is registered with a wireless network through the MTSO 110,the subroutine returns to step 506 and the device routine continues inFIG. 5.

Step 506 is followed by step 508, in which the landline network 100forwards incoming calls to the customer's landline connection 101 to thewireless communication network. For example, call forwarding isaccomplished by referencing the dialed directory number in a homelocation register (HLR) 112 located in the landline network 100. Thedialed directory number is then referenced to a directory numberassigned to the wireless communication device 206. Calls then dialed onthe landline network 100 to the assigned directory number for thecustomer premises equipment 106 win be forwarded to the directory numberassigned to the wireless communication device 206.

Step 508 is followed by step 510, where the landline network 100switches an incoming call from the landline network 100 to the wirelessnetwork. For example, in a conventional landline network, the call isrouted from the originating service switching point (SSP) 114 servicingthe caller's telephone through the PSTN 108 to a MTSO 110 servicing thewireless communication device 206 in the wireless network.

Step 510 is followed by step 512, where the wireless communicationdevice 206 receives an incoming call and the backup device 102 providestelephone service to the customer premises equipment 106 connected tothe interrupted landline connection 101. After the customer's landlinedirectory number is dialed on the landline network 100, the call isforwarded and switched from the originating service switching point(SSP) 114 through the PSTN 108 to the MTSO 110 servicing the wirelesscommunication device 206. The MTSO 110 communicates to the wirelessdevice 206 over a radio frequency or channel. The wireless device 206receives the call from the MTSO 110, and the interconnection circuit 204transfers the call to the customer premises equipment 106. Theinterconnection circuit 204 activates the ring generator 442 byswitching the ring generator 442 on and off to generate a ring on thecustomer premises equipment 106. The customer can then use the customerpremises equipment 106 to receive the incoming call.

Step 512 is followed by step 514, in which the interconnection circuit204 detects reconnection of landline service when a landline failurecondition no longer exists, or when landline telephone service isrestored to the customer premises equipment 106. The backup device 102sends a message to the MTSO 110 to unforward calls from the wirelessnetwork back to the landline network 100. For example, the MTSO 110checks an HLR 112 database for the reference of the customer premisesequipment 106 directory number in the landline network 100 to adirectory number assigned to the wireless communication device 206 ofthe interconnection circuit 204 is activated 102. The MTSO 110 removesthe reference to the wireless device 206 in the HLR 112 database inresponse to the unforward message from the interconnection circuit 204.Calls then dialed on the landline network 100 to the assigned directorynumber for the customer premises equipment 106 will not be forwarded tothe directory number assigned to the wireless communication device 206,but instead will be forwarded to the terminating service switching point(SSP) 116 originally servicing the assigned landline connection 101directory number.

Step 516 is followed by step 518, in which the MTSO 110 unswitches thecalls from the wireless network back to the landline network 100. Callsmade to the assigned directory number are no longer routed to the MTSO110 servicing the wireless communication device 206 of the backup device102, but instead calls are routed back to the terminating serviceswitching point (SSP) 116 originally servicing the directory number.

Step 518 is followed by step 520, where the interconnection circuit 204powers down the wireless communication device 206. The interconnectioncircuit 204 then restores telephone service to the customer premisesequipment 106 through the landline connection, so that calls can be madeto and from the customer using the directory number assigned to thecustomer's landline connection 101.

Step 520 is followed by step 522, in which the end of the routinereturns to the start step 500. The return step 522 permits the backupdevice 102 to constantly monitor the landline connection 101 between thecustomer premises equipment 106 and the PSTN 108.

FIG. 6 shows a logic block diagram of a routine executed by aconventional landline network 100 (as shown in FIG. 1) to support abackup device 102 (as shown in FIG. 2). Other landline networkconfigurations can be used to support the backup device 102. FIGS. 13–20show logic block diagrams describing other methods used to support abackup device 102 in modified landline network configurations.

Start step 600 initiates the support routine for a backup device 102. Tooperate in a landline communication network 100, the backup device 102communicates with the landline network 100 through a radio frequency orchannel with a mobile telephone switching office (MTSO) 110. Thelandline network 100 performs a support routine in response to theactivation of backup device 102.

Step 600 is followed by step 602, in which a MTSO 110 receives a messagefrom a wireless communication device 206 in a backup device 102 througha radio frequency. The message can contain customer locationinformation, the directory number of the customer premises equipment106, and the directory number of the wireless communication device 206.

Step 602 is followed by step 604, in which the MTSO 110 retrieves adirectory number for the wireless device 206. Typically, the messagesent by the wireless device 206 contains a directory number for thewireless device 206. If a directory number for the wireless device 206is not contained in the message, the MTSO 110 obtains a directory numberassigned to the wireless device 206. The MTSO 110 uses the directorynumber of the wireless device 206 to identify the activated backupdevice 102 and a directory number for the customer premises equipment106. The MTSO 110 uses the directory number for the customer premisesequipment 106 to identify the customer premises 104 experiencing thelandline service interruption.

Step 604 is followed by step 606, in which the MTSO 110 registers thewireless communications device 206 with a wireless communicationsnetwork connected to the landline network 100. Systems and methods forregistration of a wireless communications device 206 with a wirelesscommunication network are well known to those skilled in the art.Typically, a successful registration authenticates and authorizes awireless device 206 to communicate in a wireless network. When asuccessful registration is complete and the wireless communicationdevice 206 is operational, the support routine continues at step 608.

Following step 606 in step 608, the MTSO 110 references a database ofdirectory numbers. Typically, the database will be contained in a homelocation register (HLR) 112 or can be located at a remote location tothe HLR 112. The MTSO 110 looks up the directory number of the wirelessdevice 206 and references the directory number of the customer premisesequipment 106.

The MTSO 110 can set a database flag for the directory number of thecustomer premises equipment 106 designating that location asout-of-service (OOS). By tracking directory numbers in a database, theMTSO 110 can replace the directory number of the customer premisesequipment 106 with the directory number of the wireless device 206.Replacement of the directory number can be temporary, or can be apermanent assignment of the directory number to the wireless device 206.

Step 608 is followed by step 610, in which the MTSO 110 sets a softwaretrigger to forward calls to the directory number of the wirelesscommunication device 206. Typically, the MTSO 110 sets the softwaretrigger in a terminating service switching point (SSP) 116 servicing thecustomer's landline connection 101. The software trigger activates whenan incoming call to the customer premises equipment 106 reaches theterminating service switching point (SSP) 116.

In modified landline network configurations, a software trigger may notbe required to forward calls to the directory number of the wirelessdevice. In these configurations, the MTSO 110 executes a call forwardingsubroutine depending upon the type of call redirection device 306utilized by the modified landline network.

Step 610 is followed by step 612, where the software trigger at theterminating service switching point (SSP) 116 forwards incoming calls tothe directory number assigned to the wireless communication device 206when an incoming call to the customer premises equipment 106 arrives atthe terminating service switching point (SSP) 116. The software triggerat the terminating service switching point (SSP) 116 responds to callsmade in the landline network 100 or the wireless network, and respondsto all calls directed to the directory number of the customer premisesequipment 106. The landline network 100 executes a call forwardingsubroutine depending upon the type of call redirection device 306utilized by the landline network 100. FIGS. 13–20 show logic blockdiagrams describing other call forwarding subroutines used to support abackup device 102 in modified landline network configurations.

Step 612 is followed by step 614, in which a switch 116 routes theincoming call from the landline network 100 to the wirelesscommunication network. In a conventional landline network 100, anincoming call reaches a terminating service switching point (SSP) 116servicing a customer's landline connection 101. The terminating serviceswitching point (SSP) 116 sends the incoming call back through the PSTN108 to the MTSO 110 servicing the wireless communication device 206 ofthe backup device 102.

Step 614 is followed by step 616, in which the MTSO 110 establishestelephone service to the customer premises 104 through the backup device102. Typically, the MTSO 110 transmits the incoming call over a radiofrequency to the wireless communication device 206. The wireless device206 receives the incoming call from the MTSO 110, and theinterconnection circuit 204 of the backup device 102 connects the callfrom the wireless device 206 to the customer premises equipment 106.

The customer premises equipment 106 receives incoming voice and datainput, while it transfers outgoing voice and data output from thecustomer premises equipment 106 to the wireless device 206. The wirelessdevice 206 transmits the output by a radio frequency to the MTSO 110.The MTSO 110 forwards the output through the PSTN 108 and to the callingcustomer premises equipment. Telephone service provided by the backupdevice 102 can be terminated after the call is completed, or service canbe provided for a longer duration up to, and including the time whenlandline telephone service is reestablished.

Step 616 is followed by step 618, in which the MTSO 110 receives amessage from the landline network 100 that landline service has beenreconnected to the customer premises 104. Typically, when theinterconnection circuit 204 in the backup device 102 no longer detects afailure condition in the landline connection 101 to the customerpremises 104, the backup device 102 sends a message to the MTSO 110 thatlandline service has been reconnected. In the alternative, the localtelephone service provider or an authorized remote landline networkelement, such as a telephone service provider's central office (CO),sends a message to the MTSO 110 that landline service is reconnected,and the MTSO 110 receives the message. In either case, the customer'swireless telephone service provided by the backup device 102 deactivatesin the following steps.

Step 618 is followed by step 620, in which the MTSO 110 resets thesoftware trigger at the terminating service switching point (SSP) 116.When the software trigger is reset, the terminating service switchingpoint (SSP) 116 receives incoming calls to the directory number assignedto the customer premises equipment 106, and the software trigger doesnot activate call forwarding of the incoming call. The terminatingservice switching point (SSP) 116 treats the incoming call as a normalcall to the directory number assigned to the customer's landlineconnection 101.

Step 620 is followed by step 622, in which the MTSO 110 unforwards callsfrom the wireless communication network back to the landline network100. The database flag initially set by the MTSO 110 is removed from thedatabase, and the reference to the directory number of the wirelesscommunication device 206 set by the MTSO 110 is removed from thedatabase. Thus, the terminating service switching point (SSP) 116 routesincoming calls to the directory number of the customer premisesequipment 106 through the customer's landline connection 101.

Step 622 is followed by step 624, in which the database releases anydirectory number temporarily assigned to the wireless communicationdevice 206 if the MTSO 110 retrieved a temporary directory number instep 604. Release of the temporary directory number permits re-use ofthe directory number in the North American Numbering Plan (NANP), andreduces the threat of directory number depletion. If the directorynumber assigned to the wireless device 206 is not a temporary number,then the directory number will not be released for re-use in step 624.

Step 624 is followed by step 626, where the landline communicationsnetwork 100 provides landline telephone service to the customer'slandline connection 101. Normal landline telephone service isre-established between the landline network 100 and the customerpremises equipment 106 through the landline connection 101 to thecustomer premises 104.

Step 626 is followed by step 628, in which the support routine returnsto the start step 600 awaiting re-initiation of the routine by aninterruption in landline telephone service to the customer premises 104.

Landline Failure Analysis

FIGS. 7–12 are logic flow diagrams of a subroutine to detect landlineservice interruptions using an interconnection circuit 204 (shown inFIG. 4) in a backup device 102 (shown in FIG. 2). The subroutine can beprogrammed into a microprocessor 302 or an attached storage or memorydevice connected to the interconnection circuit 204. An example of thesubroutine begins at the start block 700 in FIG. 7.

Start block 700 is followed decision block 702, in which a line voltagedetector 412 in the interconnection circuit 204 checks the voltageacross the input wires 402 to detect whether sufficient voltagedifferential exists across the input wires 402 while the customerpremises equipment 106 is on hook.

If the voltage detector 412 detects no voltage across the input wires402, then the “NO” branch is followed to step 704. In step 704, thevoltage detector 412 sends a signal to a microprocessor 302 indicatingthat a service interruption exists. The microprocessor 302 initiates asubroutine “WTBL PROCESS 1” beginning at step 800 in FIG. 8.

Returning to decision block 702, if the voltage detector 412 detects avoltage differential across the input wires 402 equal to or greater than12 volts, then the “YES” branch is followed to decision block 706

At decision block 706, a current detector 416 measures the loop currentin the CPE telephone line 103 indicating whether the customer premisesequipment 106 is off hook. If the current detector 416 detects no loopcurrent, then the customer premises equipment 106 is on hook indicatingthat no outgoing calls are in progress. The current detector 416 sends asignal to the microprocessor 302 indicating the customer premisesequipment 106 is on hook, and the “NO” branch is followed to the startblock 700 beginning the line failure subroutine again.

If the current detector 416 does detect sufficient loop current, thenthe customer premises equipment 106 is off hook indicating that anoutgoing call may be in progress. In this case, the current detector 416sends a signal to the microprocessor 302 indicating the customerpremises equipment 106 is off hook, and the “YES” branch is followed todecision block 708.

At decision block 708, a dial tone detector 416 determines whether adial tone is being sent on the input wires 402. The detection device 304increases the strength of any dial tone signal being sent on the inputwires 402. Amplification techniques and circuitry used to amplify a dialtone signal are well-known in the art. If the dial tone detector 416does not detect a dial tone, the dial tone detector 416 sends a signalto the microprocessor 302 indicating that no dial tone is present and aservice interruption has occurred, and the “NO” branch is followed tostep 710. In step 710, the microprocessor 302 initiates a subroutine“WBTL PROCESS 2” beginning at step 900 in FIG. 9.

Returning to decision block 708, if the dial tone detector 416 detects adial tone, then the customer premises equipment 106 is still off hookand a customer may be attempting to dial a call. In this case, the “YES”branch is followed to step 712. At step 712, the microprocessor 302initiates a delay on a timer in the microprocessor 302 to wait for thecustomer to complete the attempted call. The timer can be set for adelay or a select amount of time to allow the customer to dial adirectory number.

Step 712 is followed by step 714, in which the current detector 416checks whether the customer premises equipment 106 is off hook. Asdescribed previously, the current detector 416 detects the presence ofloop current in the CPE telephone line 103. If the current detector 416detects loop current in the CPE telephone line 103 indicating thecustomer premises equipment 106 is still off hook and a call is still inprogress, then the “YES” branch is followed back up to step 712. Thisloop is repeated until the call is completed and the customer premisesequipment 106 is on hook.

Returning to decision block 714, if the current detector 416 detects noloop current indicating the call is complete, then the “NO” branch isfollowed to the beginning of the line failure subroutine at step 702.The current detector 416 sends a signal to the microprocessor 302indicating that the call is complete, and the microprocessor 302 beginsthe line failure analysis subroutine from step 702.

FIG. 8 is a logic flow diagram illustrating the steps performed when avoltage failure has occurred, that is, the voltage detector 412 does notdetect line voltage in the input wires 402. A voltage failure typicallyoccurs when the landline connection 101 between the customer premisesequipment 106 and the PSTN 108 is physically cut. When theinterconnection circuit 204 detects a voltage loss in the input wires402, the interconnection circuit 204 initiates subroutine “WBTL PROCESS1”, the voltage failure subroutine, in step 704 of FIG. 7. Step 704 isfollowed by step 800 in FIG. 8, beginning the voltage failuresubroutine.

Step 800 is followed by step 802, in which the interconnection circuit204 activates the wireless communication device 206. The interconnectioncircuit 204 activates the power supply 208 to provide power to thewireless device 206. The wireless device 206 then registers with awireless communication network, authorizing the wireless device 206 tocommunicate in the wireless network.

Step 802 is followed by step 804, in which the interconnection circuit204 activates the switch 310. The switch 310 connects the customerpremises equipment 106 to the wireless device 206 through the CPEtelephone line 103. The microprocessor 302 activates the voltagegenerator 428 to provide voltage to the CPE telephone line 103.

Following step 804 is decision block 806, in which the current detector416 determines whether the customer premises equipment 106 is off hookindicating an outgoing call attempt. If the current detector 416 detectsloop current, then the customer premises equipment 106 is off hook, andthe “YES” branch is followed to step 808. In step 808, themicroprocessor 302 initiates subroutine “Process Outgoing Call WBTL 3”to place an outgoing call on the wireless device 206.

Returning to decision block 806, if the current detector 416 detects noloop current, indicating the customer premises equipment 106 is on hook,then the “NO” branch is followed to decision block 810. At decisionblock 810, the interconnection circuit 204 determines whether anincoming call has been made to the wireless communication device 206. Ifthe microprocessor 302 detects the receipt of an incoming call on thewireless communication device 206, then the “YES” branch is followed toStep 812 to subroutine “Process Incoming Call WBTL 4” processing theincoming call. Step 812 is followed by step 1200 in FIG. 12 beginningthe subroutine.

If the wireless communication device 206 does not receive an incomingcall, then the “NO” branch is followed to decision block 814. Atdecision block 814, a voltage detector 412 determines whether voltageexists across the input wires 402. If no voltage is detected indicatingthat the a landline connection 101 voltage failure still exists, thenthe “NO” branch is followed back to decision block 806. Steps 806 and810 will repeat if the voltage failure continues and no incoming callson the wireless communication device 206 are detected by themicroprocessor 302.

Returning to decision block 814, if the voltage detector 412 detectsvoltage across the input wires 402, then the “YES” branch is followed tostep 816. At step 816, the interconnection circuit 204 deactivates thewireless device 206 by activating the switch 310 to reconnect thecustomer premises equipment 106 to the input wires 402. This disconnectsthe wireless device 206 from the customer premises equipment 106. If thewireless device 206 is a digital wireless device, the wireless device206 sends a de-registration message to the wireless network. If thewireless device 206 is an analog wireless device, the wireless device206 powers down without having to send a de-register message to thewireless network.

Step 816 is followed by step 818, in which the interconnection circuit204 deactivates the wireless device 206. Following step 818, the endstep 820 of the subroutine returns the line failure analysis subroutineto the “Process Re-entry WBTL MAIN” in step 716 of FIG. 7.

FIG. 9 is a logic flow diagram illustrating the steps performed when aterminating service switching point (SSP) 116 malfunction occurs, thatis, the dial tone detector 418 does not detect a dial tone in the inputwires 402 from the landline connection 101. When no dial tone isdetected, the microprocessor 302 initiates subroutine “WBTL PROCESS 2”in step 710 of FIG. 7. Step 710 is followed by step 900 in FIG. 9beginning the subroutine.

Step 900 is followed by step 902, in which the microprocessor 302increments a NO_DIALTONE counter located in the microprocessor 302 by asingle increment when no dial tone is detected. That is, after thecustomer premises equipment 106 is taken off hook, and the customerpremises equipment 106 is hung up without a directory number having beendialed, the NO_DIALTONE counter will be incremented by a value of 1.

Step 902 is followed by decision block 904, in which the microprocessor302 tests the NO_DIALTONE counter for a value of 3. If the NO_DIALTONEcounter has reached a value of 3 indicating that the customer premisesequipment 106 has been taken off hook three times, and after each timethe dial tone detector 418 detected no dial tone, then the “YES” branchis followed to step 906.

At step 906, the microprocessor 302 sends a signal to theinterconnection circuit 204 to activate the wireless communicationdevice 206. A power supply 208 connected to the wireless device 206provides power to the wireless device 206. The wireless communicationdevice 206 then registers with a wireless network. The wireless networkthen authorizes the wireless device 206 to communicate in the wirelessnetwork.

Step 906 is followed to step 908, where the interconnection circuit 204activates the switch 310 connecting the wireless device 206 to thecustomer premises equipment 106. The microprocessor 304 activates thevoltage generator 428 to generate a voltage on the CPE telephone line is103, permitting the customer premises equipment 106 to be used for anoutgoing call.

Step 908 is followed by step 910, in which the microprocessor 302 beginsa subroutine “WBTL PROCESS 3” when an outgoing call is in progress andno dial tone has been detected. The subroutine “WBTL PROCESS 3” beginsin step 1100 of FIG. 11.

Returning to decision block 904, in some cases a caller takes thecustomer premises equipment 106 off hook and does not listen for a dialtone before dialing, or an automatic dial function on a premises alarmsystem 122 dials without listening for a dial tone. For these instances,the value of the NO_DIALTONE counter will not reach 3, and the “NO”branch is followed to step 912.

At step 912, if a caller is dialing digits on the customer premisesequipment 106, then a dual tone multi-frequency receiver (DTMF) 418 or adial PULSE decoder collects the input digits from the customer premisesequipment 106, and stores the digits in an attached storage memory 422or dialed digit buffer.

Step 912 is followed by decision block 914, in which the currentdetector 416 determines whether the customer premises equipment 106 isoff hook; i.e. the caller is still attempting a call. If the currentdetector 416 does not detect a loop current in the CPE telephone line103 indicating that the customer premises equipment 106 is on hook andthe caller has hung up the customer premises equipment 106, then the“NO” branch is followed to step 916.

At step 916, the microprocessor 302 starts a 30-second internal timer inthe microprocessor 302 to allow the caller another opportunity to pickup the customer premises equipment 106 to attempt a call, afterinitially hanging up the customer premises equipment 106. This would bethe case when the caller is indecisive in dialing a call after pickingup the customer premises equipment 106 and not hearing a dial tone.

Step 916 is followed by decision block 918, in which the currentdetector 416 determines whether the customer premises equipment 106 isoff hook; i.e. the caller is attempting a call again. If the callerpicked up the customer premises equipment 106 and did not hear a dialtone the first time, hung up the customer premises equipment 106, andpicks up the customer premises equipment 106 a second time, the currentdetector 416 detects the second call attempt. When the current detector416 detects loop current in the CPE telephone line 103 indicating thecustomer premises equipment 106 is off hook and the caller is attemptinganother call, then the “YES” branch is followed to step 920. At step920, the microprocessor 302 returns to the line failure analysissubroutine at “Re-entry Process WBTL MAIN” in step 716 of FIG. 7.

Returning to decision block 918, if the current detector 416 does notdetect loop current in the CPE telephone line 103 indicating that thecustomer premises equipment 106 is on hook and caller has hung up, thenthe “NO” branch is followed to decision block 922.

In decision block 922, the microprocessor 302 determines whether the30-second internal timer has expired. If the timer has not expired, thenthe “NO” branch is followed back to step 918 to determine whether thecustomer premises equipment 106 is still on hook indicating that thecaller has not picked up the phone 106 a second time to attempt a call.This loop repeats until the 30-second timer has expired or until thecustomer premises equipment 106 is off hook indicating that the calleris attempting to dial a call.

Returning to decision block 922, if the microprocessor 302 determinesthat the 30-second internal timer has expired, then the “YES” branch isfollowed to step 924. At step 924, the microprocessor 302 clears theNO_DIALTONE counter, and resets the value equal to 0.

Step 924 is followed by step 926, in which the subroutine returns tobegin the line failure analysis subroutine at “Process Re-entry WBTLMAIN” at step 716 in FIG. 7.

Returning to decision block 914, if the current detector 416 detectsloop current in the CPE telephone line 103 indicating the customerpremises equipment 106 is off hook a first time, the “YES” branch isfollowed to decision block 928. In decision block 928, the DTMF receiver418 or dial PULSE decoder determines whether a complete directory numberhas been dialed on the customer premises equipment 106. A storage memory422 or storage device attached to the DTMF receiver 418 or dial PULSEdecoder stores the dialed digits. If the microprocessor 302 determinesthat the storage memory 422 does not contain a complete dialed directorynumber, then the “NO” branch is followed back to step 912 to allow theDTMF receiver 418 or dial PULSE decoder to continue collecting inputdigits. This loop continues until the customer premises equipment 106 ison hook indicating the caller has hung up, or until a complete directorynumber has been dialed.

Returning to decision block 928, if the microprocessor 302 determinesthat the storage memory 422 contains a complete dialed directory number,then the “YES” branch is followed to decision block 930. In decisionblock 930, a call progress monitor 424 determines whether there are anycall progress signals on the input wires 402 indicating that the dialeddirectory number is being connected through the landline network 100.Examples of call progress signals include, but are not limited to,detecting whether a dial tone is being transmitted indicating end ofcall, or whether a busy signal is being transmitted indicating noconnection, or whether a ringing signal is being transmitted indicatingthat the call has not yet been connected.

If the call progress monitor 424 detects that the call was successfullyconnected, then the “YES” branch is followed to step 932. In step 932,the microprocessor 302 clears the storage memory 422.

Step 932 is followed by step 934, in which the microprocessor 302 clearsthe NO_DIALTONE counter, setting the value to zero. Step 934 is followedby step 936, where the line failure analysis subroutine begins again at“Process Re-entry WBTL MAIN” at step 716 in FIG. 7.

Returning to decision block 930, if the call progress monitor 424 doesnot detect any call progress signals on the input wires 402 indicatingthat no call has been successfully connected, then the “NO” branch isfollowed to step 938. In step 938, the microprocessor 302 begins a25-second internal timer located in the microprocessor 302 to allow thedialed call to be connected through the landline network 100. Theduration of time set for the timer can be any amount of time necessaryto wait for the call to be connected through the landline network 100.

Following step 938 in decision block 940, the microprocessor 302 checkswhether the 25-second internal timer has expired. If the timer hasexpired, then the “YES” branch is followed to step 942. Step 942 isfollowed by step 1000 in FIG. 10.

Turning now to FIG. 10, the subroutine continues in step 1000. Step 1000is followed by step 1002, in which the microprocessor 302 activatesswitch 310. The switch 310 connects the wireless device 206 with thecustomer premises equipment 106. The microprocessor activates thevoltage generator 428 to provide a voltage on the CPE telephone line103.

Step 1000 is followed by step 1002, in which the DTMF receiver 418 ordial PULSE decoder forwards the collected dialed digits through theinput wires 402 to the wireless communication device 206. The wirelesscommunication device 206 initiates a call on the wireless network bytransmitting the dialed digits by a radio frequency to a mobiletelephone switching office (MTSO) 110 shown in FIG. 1.

Step 1002 is followed by step 1004, in which the current detector 416detects whether the customer premises equipment 106 is off hook. If thecurrent detector 416 detects loop current in the CPE telephone line 103indicating the customer premises equipment 106 is still off hook and acall is still being attempted, then the “YES” branch is followed torepeat step 1006 again.

When the current detector 416 detects no loop current indicating thecustomer premises equipment 106 is on hook and the call has beenterminated or completed, then the “NO” branch is followed to step 1008.At step 1008, the microprocessor 302 returns to the line failureanalysis subroutine “Process Re-entry WBTL MAIN” at step 716 in FIG. 7.

Returning to decision block 938 in FIG. 9, if the 25-second internaltimer has not expired, then the “NO” branch is followed to step 944. Instep 944, the current detector 416 detects loop current in the CPEtelephone line 103 indicating whether the customer premises equipment106 is off hook and a call is being attempted.

If loop current is detected, then the “YES” branch is followed to step930. At step 930, the call progress monitor 424 detects call progresssignals at the customer premises equipment 106 indicating whether a callis in progress. This loop continues until either call progress signalsare detected by the call progress monitor 424 or the 25-second timerexpires.

Returning to decision block 944, if the current detector 416 does notdetect loop current in the input wires 402, then the “NO” branch isfollowed to step 946 returning to the line failure analysis subroutineat “Process Re-entry WTBL MAIN” in step 716 of FIG. 7.

FIG. 11 is a logic flow diagram illustrating the steps of initiating anoutgoing call from the backup device 102. Subroutine “WBTL PROCESS 3”begins at the start block 1100. Step 1100 is followed by step 1102, inwhich a dial tone generator 434 creates a dial tone for the customerpremises equipment 106. To generate dial tone, the interconnectioncircuit 204 activates the dial tone generator 434 and a dial tone isgenerated through the CPE telephone line 103 to the customer premisesequipment 106. Different dial tones can be generated to indicatedifferent landline failure conditions.

Step 1102 is followed by step 1104, in which the DTMF receiver 418 ordial PULSE decoder collects input digits dialed from the customerpremises equipment 106. The storage memory 422 stores the dialed digits.

Step 1104 is followed by step 1106, in which the interconnection circuit204 deactivates the dial tone generator 434 if a digit has been entered.From the caller's perspective, the customer premises equipment 106 emitsa dial tone as if normal landline service is being supplied and when adigit is dialed into the customer premises equipment 106 by the caller,the dial tone ceases to be heard by the caller.

Following step 1106 in decision block 1108, the microprocessor 302determines whether dialing is complete by detecting whether a completedirectory number has been input into the customer premises equipment106. If a complete directory number has not been input, then the “NO”branch is followed to decision block 1110.

In decision block 1110, a current detector 416 detects whethersufficient loop current exists in the CPE telephone line 103, i.e. thecustomer premises equipment 106 is off the hook. If loop current is notdetected indicating the customer premises equipment 106 is on hook, thenstep 1110 is followed by step 1112. Step 1112 returns to the linefailure analysis subroutine at step 716 “Re-enter Process WBTL MAIN” inFIG. 7.

Returning to decision block 1110, if current detector 416 detects loopcurrent in the CPE telephone line 103 indicating the caller has notfinished dialing a complete directory number, then the “YES” branch isfollowed to step 1104. In step 1104, the storage memory 422 continues tocollect input digits from the DTMF receiver 418 or dial PULSE decoder.This loop repeats until a complete directory number is dialed or untilthe current detector 416 detects no loop indicating the customerpremises equipment 106 is on hook.

Returning to decision block 1108, if the microprocessor 302 determinesthat a complete directory number has been dialed, then the “YES” branchis followed to step 1114. In step 1114, the storage memory 422 forwardsthe collected digits to the wireless communication device 206. Thewireless communication device 206 transmits the collected digits to thewireless network initiating a call using the dialed directory number.

Step 1114 is followed by decision block 1116, in which the currentdetector 416 determines whether loop current exists in the CPE telephoneline 103 indicating the customer premises equipment 106 is off hook. Ifthe current detector 416 detects loop current indicating the customerpremises equipment 106 is off hook, then the “YES” branch is followedback to repeat the query at decision block 1116 until no loop current isdetected in the input wires 402.

When the current detector 416 detects no loop current indicating thecustomer premises equipment 106 is on hook and the call is complete,then the “NO” branch is followed to step 1118. Step 1118 returns to linefailure analysis subroutine at step 716 “Re-enter Process WBTL MAIN” inFIG. 7.

FIG. 12 illustrates subroutine “WBTL PROCESS 4”, the steps to receive anincoming call on the backup device 102. The start step at 1200 initiatesthe subroutine. Step 1200 is followed by step 1202, in which theinterconnection circuit 204 activates a ring generator 442. The ringgenerator 442 generates a ringing voltage on the CPE telephone line 103to create an audible ring sound on the customer premises equipment 106,if ring equipment is available, indicating that an incoming call hasarrived. Different ring cycles may be activated depending upon the linefailure condition detected by the interconnection circuit 204. A typicalring cycle used to indicate an incoming call is two seconds on and fourseconds off, that is, the interconnection circuit 204 supplies voltageto the ring generator 442 for two seconds and cuts voltage for fourseconds.

Step 1202 is followed by decision block 1204, in which the currentdetector 416 determines whether loop current is present the CPEtelephone line 103 indicating whether the incoming call has beenanswered. If the current detector 416 detects no loop current indicatingthe customer premises equipment 106 is on hook and the call remainsunanswered, then the “NO” branch is followed to decision block 1206.

In decision block 1206, the microprocessor 302 checks the wirelesscommunication device 206 to determine whether the incoming call is stillon line. If the call is not on line indicating the caller has hung up,then the NO” branch is followed to step 1208 re-entering the linefailure analysis subroutine at “Re-entry Process WBTL MAIN” step 716 inFIG. 7.

Returning to decision block 1206, if the call is still on lineindicating the caller has not hung up, then the “YES” branch is followedfrom decision block 1206 back to step 1202. In step 1202, theinterconnection circuit 204 activates the ring generator 442. This loopis continued until the current detector 416 detects loop current in theCPE telephone line 103 indicating the call has been answered, or untilno call is detected on the wireless communication device 206 indicatingthe caller has hung up.

Returning to decision block 1204, if the current detector 416 detectscurrent in the CPE telephone line 103 indicating that the customerpremises equipment 106 is off hook and thus has been answered, then the“YES” branch is followed to step 1210.

In step 1210, the interconnection circuit 204 connects the customerpremises telephone 106 equipment to wireless communication device 206.

Step 1210 is followed by decision block 1212, in which the currentdetector 416 determines whether no loop current is present in the CPEtelephone line 103 indicating the end of the call. If the currentdetector 416 detects loop current, indicating that the customer premisestelephone 106 is off hook and the call is still in progress, then the“YES” branch is followed back to repeat the query in decision block1212. This loop repeats until the current detector 416 detects no loopcurrent in the CPE telephone line 103 indicating call completion.

If the current detector 416 detects no loop current in the CPE telephoneline 103 indicating that the customer premises telephone 106 is on hookand the call has ended, then the “NO” branch is followed to the step1214. Step 1214 returns to the line failure analysis subroutine at“Re-entry Process WBTL MAIN” at step 716 in FIG. 7.

Call Forwarding Methods

The invention utilizes the conventional landline network 100 withoutrequiring significant modification to the backup device 102 device or tothe landline network 100. For example, FIGS. 13–14 show a logic blockdiagram describing the steps taken by a conventional landline network100 to deliver a call to a backup device 102.

Step 1300 initiates a routine when the subscriber's landline telephoneservice is interrupted. Step 1300 is followed by step 1302, in which awireless communication device 206 powers up in the backup device 102. Apre-assigned or pre-programmed mobile identification number (MIN)identifies the wireless communication device 206 in a wireless network.A virtual MIN or a standard MIN can be used to identify the wirelessdevice 206. A virtual MIN cannot normally be dialed in the conventionallandline network 100 to reach the wireless device 206 or any otherlandline telephone. If a caller dials the virtual MIN, the caller may berequired to dial an additional local access number before dialing thevirtual MIN to place a call to the backup device 102 after the wirelessdevice 206 has been activated.

Alternatively, a standard cellular directory number can be assigned tothe wireless device 206, or the directory number assigned to thecustomer's landline connection 101 can be assigned to the wirelessdevice 206. If a caller dials the standard cellular number, or dials thecustomer's landline number if the customer's own landline number isassigned to the wireless device, the backup device 102 may receivecalls. However, the caller may require knowledge of the assigneddirectory number, or the caller may be required to dial an additionallocal access number before dialing the assigned directory number to beable to place a call to the backup device 102 when landline service hasbeen interrupted.

Step 1302 is followed by step 1304, where the wireless device 206 sendsa message to a home location register (HLR) 112 internal to or attachedto a mobile telephone switching office (MTSO) 110 to register with thewireless network. The wireless device 206 could also send a message toany type of local serving cellular switch to register the wirelesscommunication device 206 with the serving wireless network.

After the wireless communication device 206 completes registration, step1304 is followed by step 1306 in which a software trigger embedded inthe MTSO 110 sends a flag to the HLR 112 database indicating that abackup device 102 has registered with the wireless network. The softwaretrigger initiates an out-of-service (OOS) flag placed with the HLR 112database indicating that the subscriber's landline 101 service has beeninterrupted. A software trigger can be embedded in any call redirectiondevice, such as a HLR 112 or a local number portability platform (LNPP)118. The call redirection device then sends a flag to an internal orattached database, such as an HLR 112 database or a service controlpoint (SCP) 120 database.

In the alternative, an ancillary “snooping” system can monitor SS-7links looking for backup device 102 devices to register when a backupdevice 102 sends a registration message to the serving cellular switch.After finding a registration message from a backup device 102 in thelandline network 100, the ancillary system can set an OOS flag with adatabase. The ancillary “snooping system” functions as the equivalent toa software trigger.

Step 1306 is followed by step 1308, in which the HLR 112 databasecorrelates the MIN assigned to the wireless communication device 206with the directory number assigned to the subscriber's landlineconnection 101 at the site of service interruption.

Any time a database performs a correlation between a MIN and a landlinedirectory number, a message can be sent to a maintenance centernotifying the telephone service provider that landline service has beeninterrupted at the location served by the landline directory number.

Step 1308 is followed by step 1310, in which an interval timer in theMTSO 110 starts a count of 17 minutes. Any other time interval can beused so long as the time used is longer than the registration interval(REG_INCR) of the wireless network. Setting the interval timer for atime longer than the registration interval ensures that at least part ofthe wireless network registration interval will be within the timecounted by Is the interval timer. The registration interval is definedas the time between a successful wireless network registration by awireless device and the time the wireless network automaticallyde-registers the wireless device. For example, the registration intervalin FIG. 13 starts at a count of 15 minutes, after 15 minutes haselapsed; the wireless device 206 is automatically de-registered.

Step 1310 is followed by step 1312, in which a call forward message issent to a terminating service switching point (SSP) 116 or the localserving landline switch. The MTSO 110 or the HLR 112 sends a messagecontaining a call redirect flag, a serving system ID, and the MIN of thewireless communication device 206 to the terminating service switchingpoint (SSP) 116. This step implants the MIN into the terminating serviceswitching point (SSP) 116 for use by the switch in redirecting callsmade to the landline directory number. The terminating service switchingpoint (SSP) 116 stores this information until the interval timer expiresor until the terminating service switching point (SSP) 116 utilizes thestored information for an incoming call.

Step 1312 is followed by step 1314, in which the interval timercontinues to run, permitting extra time for an incoming call to arriveat the terminating service switching point (SSP) 116. Step 1314 in FIG.13 corresponds to step 1314 in FIG. 14.

Turning to FIG. 14, step 1314 is followed by decision block 1316, inwhich the terminating service switching point (SSP) 116 detects whetheran incoming call has been placed to the subscriber's landline directorynumber. If an incoming call is detected, the “YES” branch is followed tostep 1318.

In step 1318, the terminating service switching point (SSP) 116 receivesthe incoming call, and the terminating service switching point (SSP) 116uses the MIN to redirect the call to the MTSO 110. The terminatingservice switching point (SSP) 116 routes the call to the cellularserving switch, and the terminating service switching point (SSP) 116routes the call to the MTSO 110 for transmission over a radio frequencyto the backup device 102. Any other conventional call forwarding methodcan be used in step 1318 so long as the MIN is used to redirect theincoming call to the wireless communication device 206 of the backupdevice 102.

Step 1318 is followed by step 1320, in which the call is completed and areturn to step 1314 waits for another incoming call.

Returning to decision block 1316, if the terminating service switchingpoint (SSP) 116 does not detect an incoming call to the subscriber'slandline directory number, then the “NO” branch is followed to decisionblock 1322.

Decision block 1316 is followed by decision block 1322, in which theMTSO 110 detects whether the wireless communication device 206 has sentanother registration message to the MTSO 110 to register with thewireless network. If a successful registration has been made with thewireless network, then the “YES” branch is followed to step 1324.

In step 1324, the MTSO 110 resets the interval timer. Step 1324 isfollowed by step 1326, in which the interval timer starts a count downfrom 17 minutes or from another set time. Step 1326 is followed by step1328, returning to step 1314 waiting for an incoming call.

Returning to decision block 1322, if the MTSO 110 does not detectanother registration or the registration failed for any reason, then thewireless communication device 206 will no longer be currently registeredon the wireless network and the “NO” branch will be followed to decisionblock 1330.

At decision block 1330, the MTSO 110 detects whether the wirelesscommunication device 206 de-registered from the wireless network. If thewireless communication device 206 has not de-registered from thewireless network, then the “NO” branch is followed to decision block1332. At decision block 1332, the MTSO determines if an interval timeouthas occurred. If an interval timeout has not occurred then the “NO”branch is followed to decision block 1316. At decision block 1316, theMTSO 110 again detects whether an incoming call to the subscriber'slandline directory number has been made. This loop continues until theMTSO 110 detects a new registration of the wireless device 206 or untilthe wireless device 206 de-registers from the wireless network.

Returning to decision block 1332, if an interval timeout has occurred,the “YES” branch is followed to step 1334. For some digital wirelessdevices and most analog wireless communication devices that do notperform a de-registration from the wireless network, the intervaltimeout performs the equivalent function as a de-registration.

Returning to decision block 1330, if the wireless communication device206 has de-registered from the wireless network, then the “YES” branchis followed to step 1334. Ade-registration is typically performed by adigital wireless communication device. Some digital wireless devices andmost analog wireless communication devices do not perform ade-registration from the wireless network.

Decision block 1330 is followed by step 1334, in which the MTSO 110restores the landline directory number in the terminating serviceswitching point (SSP) 116, removing all flags and pointers that hadpreviously been set within the MTSO 110 and the HLR 112 database.

Step 1334 is followed by step 1336, returning to start block 1300 inFIG. 13 waiting for a subscriber's landline connection to fail.

Future telecommunication equipment upgrades and technological advancesin the landline network are anticipated. Several methods of deliveringcalls through modified landline network components are described asfollows. For example, in a landline network 100 using a local numberportability platform (LNPP) 118, the LNPP 118 functions as a callredirection device. FIGS. 15–16, 17–18, and 19–20 describe threedifferent logic block diagrams illustrating the steps taken by alandline network utilizing a modified LNPP to deliver a call to a backupdevice 102.

In start block 1500, the routine begins when the subscriber's landlinetelephone service is interrupted. Step 1500 is followed by step 1502, inwhich the backup device 102 powers up a wireless communication device206. A pre-assigned or preprogrammed real mobile identification number(MIN) identifies the wireless communication device 206 in a wirelessnetwork.

Step 1502 is followed by step 1504, in which the backup device 102 sendsa message to a mobile telephone switching office (MTSO) 110 or aninternal or attached home location register (HLR) 112, or any otherlocal serving cellular switch, to register the wireless communicationdevice 206 with the serving wireless network.

Step 1504 is followed by step 1506, in which a software trigger embeddedin the MTSO 110 or the HLR 112 software activates a database flag. Thesoftware trigger initiates a call forward record or an out-of-service(OOS) flag placed with the MTSO 110 or the HLR 112, indicating that thesubscriber's landline service has been interrupted.

Step 1506 is followed by step 1508, in which a database associated withthe MTSO 110 or the HLR 112 correlates the MIN assigned to the wirelesscommunication device 206 with the directory number assigned to thelandline connection 101 the site of service interruption.

Step 1508 is followed by step 1510, in which an interval timer in theMTSO 110 starts a count of 17 minutes, or any other time longer than theregistration interval (REG_NCR) of the wireless network. In thisexample, the registration interval starts at a count of 15 minutes.

Step 1510 is followed by step 1512, in which the MTSO 110 sends a callredirect message to the LNPP 118. The call redirect message contains acall redirect flag, a serving system ID, and the real MIN of thewireless communication device 206. The LNPP 118 redirects calls todirectory numbers from the point of origination at the time of the callattempt. The LNPP 118 stores the call redirect flag, the serving systemID, and the real MIN until the interval timer expires or until thelandline directory number is restored.

Step 1512 is followed by step 1514, in which the interval timercontinues to run, waiting for an incoming call to the originatingservice switching point (SSP) 114. Step 1514 corresponds to step 1514 inFIG. 16.

Turning to FIG. 16, step 1514 is followed by decision block 1516, inwhich the originating service switching point (SSP) 114 detects whetheran incoming call has been placed to the subscriber's landline directorynumber. If an incoming call is detected, the “YES” branch is followed tostep 1518.

In step 1518, the originating service switching point (SSP) 114 receivesthe incoming call, and sends a SS-7 route request to the LNPP 118.

Step 1518 is followed by step 1520, in which the LNPP 118 responds tothe SS-7 route request by sending a message with the MIN for thewireless communication device 206 instead of the landline directorynumber.

Step 1520 is followed by step 1522, in which the originating serviceswitching point (SSP) 114 uses the received message with the real MIN toredirect the call to the MTSO 110. The originating service switchingpoint (SSP) 114 routes the call to the MTSO 110 for transmission over aradio frequency to the backup device 102.

Step 1522 is followed by step 1524, in which the MTSO 110 waits for callcompletion, and then the routine returns to step 1514 to wait for anincoming call.

Returning to decision block 1516, if the originating service switchingpoint (SSP) 114 does not detect an incoming call to the subscriber'slandline directory number, then the “NO” branch is followed to decisionblock 1526.

At decision block 1526, the MTSO 110 detects whether the wirelesscommunication device 206 has sent another registration message toregister with the wireless network. If a successful registration hasbeen made, then the “YES” branch is followed to step 1528.

In step 1528, the MTSO 110 resets the interval timer. Step 1528 isfollowed by step 1530, in which the interval timer starts a count downfrom 17 minutes or from another set time. Step 1530 is followed by step1532, returning to the step 1314 to wait for an incoming call.

Returning to decision block 1526, if the MTSO 110 does not detectanother registration or the registration failed for any reason, then thewireless communication device 206 will no longer be currently registeredon the wireless network and the “NO” branch will be followed to decisionblock 1534.

At decision block 1534, the MTSO 110 detects whether the wirelesscommunication device 206 de-registered from the wireless network. If thewireless communication device 206 has de-registered from the wirelessnetwork, then the “YES” branch is followed to step 1538. Ade-registration is typically performed by a digital wirelesscommunication device. Some digital wireless devices and most analogwireless communication devices do not perform a de-registration from thewireless network.

If the wireless communication device has not de-registered from thewireless network, then the “NO” branch is followed to decision block1536. At decision block 1536, the MTSO 110 determines whether aninterval timeout has occurred. If an interval timeout has not occurredthen the “NO” branch is followed back to the decision block 1516. Atdecision block 1516, the MTSO 110 again detects whether an incoming callto the subscriber's landline directory number has been made. This loopcontinues until the MTSO 110 detects a new registration of the wirelessdevice 206 or until the wireless device 206 de-registers from thewireless network.

Returning to decision block 1536, if an interval timeout has occurred,then the “YES” branch is followed to step 1538. For the digital wirelessdevices and most analog wireless communication devices that do notperform a de-registration from the wireless network, the intervaltimeout performs the equivalent function as a de-registration.

In step 1538, the MTSO 110 restores the landline directory number in theLNPP 118, by removing all flags and pointers that had previously beenset within the originating service switching point (SSP) 114. Step 1538is followed by step 1540, returning to the start block 1500 in FIG. 15waiting for a subscriber's landline connection 101 to fail.

FIGS. 17–18 illustrate a preferred embodiment of the invention. In startblock 1700, the routine begins when the subscriber's landline telephoneservice is interrupted. Step 1700 is followed by step 1702, in which thebackup device 102 powers up a wireless communication device 206. Apre-assigned or preprogrammed virtual mobile identification number (MIN)identifies the wireless communication device 206 in a wireless network.

Step 1702 is followed by step 1704, in which the wireless communicationdevice 206 sends a message to a MTSO 110 or an attached HLR 112 toregister the wireless device 206 with the serving wireless network.

Step 1704 is followed by step 1706, in which a software trigger embeddedin the MTSO 110 or the HLR 112 software activates a database flag. Thetrigger initiates a call forward record or an out-of-service (OOS) flagplaced with the local MTSO 110 or the HLR 112, indicating that thebackup device 102 subscriber's landline service has been interrupted.

Step 1706 is followed by step 1708, in which a database associated withthe MTSO 110 or the HLR 112 correlates the virtual MIN assigned to thewireless communication device 206 with the landline directory number atthe site of service interruption.

Step 1708 is followed by step 1710, an interval timer at the MTSO 110starts a count of 17 minutes, or any other time longer than theregistration interval (REG_INCR) of the wireless network. In thisexample, the registration interval starts at a count of 15 minutes.

Step 1710 is followed by step 1712, in which the MTSO 110 sends a callredirect message to a modified LNPP 118. The modified LNPP 118 has beenmodified to support the backup device 102. The call redirect messagecontains a call redirect flag, a serving system ID, and the virtual MINof the wireless communication device 206. The LNPP 118 redirects callsto directory numbers from the point of origination at the time of thecall attempt. The LNPP 118 stores the call redirect flag, the servingsystem ID, and the virtual MIN until the interval timer expires or untilthe landline directory number is restored.

Step 1712 is followed by step 1714, in which the interval timercontinues to run waiting for an incoming call to an originating serviceswitching point (SSP) 114. Step 1714 corresponds to step 1714 in FIG.18.

Turning to FIG. 18, step 1714 is followed by decision block 1716, inwhich the originating service switching point (SSP) 114 detects whetheran incoming call has been placed to the subscriber's landline directorynumber. If an incoming call is detected, the “YES” branch is followed tostep 1718.

In step 1718, the originating service switching point (SSP) 114 receivesthe incoming call, and the originating service switching point (SSP) 114sends a SS-7 route request to the LNPP 118.

Step 1718 is followed by step 1720, in which the LNPP 118 responds tothe SS-7 route request by sending an IS-41 route request or MAP routerequest over the North American wireless network to the MTSO 110identified by the serving system ID. The route request contains theserving system ID and the virtual MIN.

Step 1720 is followed by step 1722, in which the MTSO 110 uses thereceived IS-41 route request with the serving system ID and the virtualMIN to respond to the LNPP 118 with a temporary directory number (TLDN)for the wireless communication device 206.

Step 1722 is followed by step 1724, in which the LNPP 118 responds tothe route request from the originating service switching point (SSP) 114by sending the TLDN for the wireless communication device 206 to theoriginating service switching point (SSP) 114.

Step 1724 is followed by step 1726, in which the originating serviceswitching point (SSP) 114 redirects the call by routing the call to theMTSO 110, and the MTSO 110 sends the call over a radio frequency to thebackup device 102. At the instant that the wireless device 206 answersthe incoming call, the MTSO 110 releases the TLDN back for re-use orre-assignment.

Step 1726 is followed by step 1728, in which the MTSO 110 detects callcompletion. Step 1728 returns to step 1714 to wait for another incomingcall to the subscriber's landline directory number.

Returning to decision block 1716, if the originating service switchingpoint (SSP) 114 does not detect an incoming call to the subscriber'slandline directory number, then the “NO” branch is followed to decisionblock 1730.

At decision block 1730, the MTSO 110 detects whether the wirelesscommunication device 206 has sent another registration message toregister with the wireless network. If a successful registration hasbeen made, then the “YES” branch is followed to step 1732.

In step 1732, the MTSO 110 resets the interval timer. Step 1732 isfollowed by step 1734, in which the interval timer starts a count downfrom 17 minutes or from another set time. Step 1734 is followed by step1736, returning to step 1714 waiting for another incoming call to theoriginating service switching point (SSP) 114.

Returning to decision block 1730, if the MTSO 110 does not detectanother registration or the registration failed for any reason, then thewireless communication device 206 will no longer be currently registeredon the wireless network and the “NO” branch will be followed to decisionblock 1738.

At decision block 1738, the MTSO 110 detects whether the wirelesscommunication device 206 de-registered from the wireless network. If thewireless communication device 206 has de-registered from the wirelessnetwork, then the “YES” branch is followed to step 1742. Ade-registration is typically performed by a digital wirelesscommunication device. Some digital wireless devices and most analogwireless communication devices do not perform a de-registration from thewireless network.

If the wireless communication device 206 has not de-registered from thewireless network, then the “NO” branch is followed to decision block1740. At decision block 1740, the MTSO 110 determines whether aninterval timeout has occurred. If the MTSO 110 determines that aninterval timeout has not occurred, then the “NO” branch is followed backto decision block 1716. At decision block 1716, the originating serviceswitching point (SSP) 114 again determines whether an incoming call tothe subscriber's landline directory number has been received. This loopcontinues until an incoming call is received at the originating serviceswitching point (SSP) 114, until the wireless device 206 registersagain, until the wireless device 206 de-registers with the wirelessnetwork, or until the MTSO 110 detects an interval timeout.

Returning to decision block 1740, if an interval timeout has occurred,the “YES” branch is followed to step 1742. For some digital wirelessdevices and most analog wireless communication devices that do notperform a de-registration from the wireless network, the intervaltimeout performs the equivalent function as a de-registration.

In step 1742, the MTSO 110 restores the landline directory number in theLNPP 118 by removing all flags and pointers that had previously been setwithin the MTSO 110 or connected HLR 112 database. Step 1742 is followedby step 1744, returning to the start block 1700 in FIG. 17 waiting for asubscriber's landline connection to fail.

FIGS. 19–20 illustrate another embodiment of a call forwarding routine.In this embodiment, a block of temporary line directory numbers (TLDN)are reserved within the North American Numbering Plan (NANP). In startblock 1900, the routine begins when the subscriber's landline telephoneservice is interrupted. Step 1900 is followed by step 1902, in which thebackup device 102 powers up a wireless communication device 206. Apre-assigned or preprogrammed virtual mobile identification number (MIN)identifies the wireless communication device 206 in a wireless network.When the wireless communication device 206 is powered down, the virtualMIN will be restored when the wireless device is subsequently poweredon, and any temporary MIN assigned to the wireless device 206 will becleared.

Step 1902 is followed by step 1904, in which the wireless communicationdevice 206 sends a message to a MTSO 110 or an attached HLR 112 toregister the wireless device 206 with the serving wireless network.

Step 1904 is followed by step 1906, in which a software trigger embeddedin the MTSO 110 or the HLR 112 software activates a database flag. Thetrigger initiates a call forward record or an out-of-service (OOS) flagplaced with the local MTSO 110 or the HLR 112, indicating that thebackup device 102 subscriber's landline service has been interrupted.

Step 1906 is followed by step 1908, in which a database associated withthe MTSO 110 or the HLR 112 correlates the virtual MIN assigned to thewireless communication device 206 with the landline directory number atthe site of service interruption.

Step 1908 is followed by step 1910, in which the database assigns a newtemporary real MIN or temporary directory number to the wireless device206.

Step 1910 is followed by step 1912, in which the wireless networkinitiates an over-the-air activation of the backup device 102. Thebackup device is activated by the MTSO by sending a message containing areal directory number from a reserved block of directory numbers.Conventional over-the-air activation methods are used to program thewireless communication device 206 in the backup device 102 with a realdirectory number from a reserved block of temporary directory numbers.The reserved numbers will only be assigned to a backup device when thebackup device is operating. Variations of directory number assignmentprogram a standard cellular directory number into the wireless devicevia over-the-air activation methods.

Step 1912 is followed by step 1914, in which an interval timer at theMTSO 110 starts a count of 17 minutes, or any other time longer than theregistration interval (REG_INCR) of the wireless network. In thisexample, the registration interval starts at a count of 15 minutes.

Step 1914 is followed by step 1916, in which the MTSO 110 sends a callredirect message to a LNPP 118. The call redirect message contains acall redirect flag, a serving system ID, and the temporary real MIN ofthe wireless communication device 206. The LNPP 118 redirects calls todirectory numbers from the point of origination at the time of the callattempt. The LNPP 118 stores the call redirect flag, the serving systemID, and the temporary real MIN until the interval timer expires or untilthe landline directory number is restored. Variations of this methodutilize any type of remote call forwarding platform updated with atemporary real MIN or a standard directory number.

Step 1916 is followed by step 1918, in which the interval timercontinues to run waiting for an incoming call to an originating serviceswitching point (SSP) 114. Step 1918 corresponds to step 1918 in FIG.18.

Turning to FIG. 20, step 1918 is followed by decision block 1920, inwhich the originating service switching point (SSP) 114 detects whetheran incoming call has been placed to the subscriber's landline directorynumber. If an incoming call is detected, the “YES” branch is followed tostep 1922.

In step 1922, the originating service switching point (SSP) 114 sends aSS-7 route request to the LNPP 118.

Step 1922 is followed by step 1924, in which the LNPP 118 responds tothe SS-7 route request from the originating service switching point(SSP) 114 by sending a return message containing the temporary real MINassigned to the wireless communication device 206 back to theoriginating service switching point (SSP) 114.

Step 1924 is followed by step 1926, in which the originating serviceswitching point (SSP) 114 redirects the call by routing the call to theMTSO 110, and the MTSO 110 sends the call over a radio frequency to thebackup device 102.

Step 1926 is followed by step 1928, in which the MTSO 110 detects callcompletion. Step 1928 returns to step 1918 to wait for another incomingcall to the subscriber's landline directory number.

Returning to decision block 1920, if the originating service switchingpoint (SSP) 114 does not detect an incoming call to the subscriber'slandline directory number, then the “NO” branch is followed to decisionblock 1930.

At decision block 1930, the MTSO 110 detects whether the wirelesscommunication device 206 has sent another registration message toregister with the wireless network. If a successful registration hasbeen made, then the “YES” branch is followed to step 1932.

In step 1932, the MTSO 110 resets the interval timer. Step 1932 isfollowed by step 1934, in which the interval timer starts a count downfrom 17 minutes or from another set time. Step 1934 is followed by step1936, returning to step 1918 waiting for another incoming call to theoriginating service switching point (SSP) 114.

Returning to decision block 1930, if the MTSO 110 does not detectanother registration or the registration failed for any reason, then thewireless communication device 206 will no longer be currently registeredon the wireless network and the “NO” branch will be followed to decisionblock 1940.

At decision block 1938, the MTSO 110 detects whether the wirelesscommunication device 206 de-registered from the wireless network. If thewireless communication device 206 has de-registered from the wirelessnetwork, then the “YES” branch is followed to step 1942. Ade-registration is typically performed by a digital wirelesscommunication device. Some digital wireless devices and most analogwireless communication devices do not perform a de-registration from thewireless network.

If the wireless communication device 206 has not de-registered from thewireless network, then the “NO” branch is followed to decision block1940. At decision block 1940, the MTSO 110 determines whether aninterval timeout has occurred. If the MTSO 110 determines that aninterval timeout has not occurred, then the “NO” branch is followed backto decision block 1920. At decision block 1920, the originating serviceswitching point (SSP) 114 again determines whether an incoming call tothe subscriber's landline directory number has been received. This loopcontinues until an incoming call is received at the originating serviceswitching point (SSP) 114, until the wireless device 206 registersagain, until the wireless device 206 de-registers with the wirelessnetwork, or until the MTSO 110 detects an interval timeout.

Returning to decision block 1940, if an interval timeout has occurred,the “YES” branch is followed to step 1942. For some digital wirelessdevices and most analog wireless communication devices that do notperform a de-registration from the wireless network, the intervaltimeout performs the equivalent function as a de-registration.

In step 1942, the MTSO 110 restores the landline directory number in theLNPP 118 by removing all flags and pointers that had previously been setwithin the MTSO 110 or connected HLR 112 database. Furthermore, uponeither de-registration of the wireless device 206 or upon an intervaltimeout, the temporary real MIN assigned to the wireless device 206 isreleased, and the virtual MIN assigned to the wireless device 206 isrestored. Step 1942 is followed by step 1944, returning to the startblock 1900 in FIG. 19 waiting for a subscriber's landline connection tofail.

In view of the foregoing, it will be appreciated that the inventionprovides an improved backup device for landline telephone equipment. Itwill be understood that the preferred embodiment has been disclosed byway of example, and that other modifications may occur to those skilledin the art without departing from the scope and spirit of the appendedclaims.

1. A wireless backup telephone device for providing emergency backuptelephone service to customer premises telephone equipment connectedthrough a landline to a telephone network, the device operable for:detecting an interruption of telephone service provided by the landlineto the customer premises equipment; in response to detecting theinterruption, powering a wireless communication device operable forcommunicating with a wireless network; switching the customer premisesequipment to be functionally connected to the wireless communicationdevice; transmitting a message instructing a telephone call redirectiondevice to forward telephone calls directed to a directory numberassigned to the customer premises telephone equipment to a directorynumber assigned to the wireless communication device; and providingemergency backup telephone service to the customer premises telephoneequipment through the wireless communication device.
 2. The wirelessbackup telephone device of claim 1, further comprising a voltagegenerator, a ring generator, and a dial tone generator for providingemergency backup telephone service to the customer premises telephoneequipment.
 3. The wireless backup telephone device of claim 1, furtheroperable for: detecting resumption of telephone service provided by thelandline to the customer premises equipment while the customer premisesequipment is functionally connected to the wireless communicationdevice; switching the customer premises equipment to be disconnected tothe wireless communication device; and powering down the wirelesscommunication device.
 4. The wireless backup telephone device of claim3, further operable for: transmitting a message instructing a telephonecall redirection device to unforward telephone calls to the directorynumber assigned to the wireless communication device to the directorynumber assigned to the customer premises telephone equipment.
 5. Thewireless backup telephone device of claim 3, further operable fordetecting resumption of telephone service provided by the landline tothe customer premises telephone equipment by: detecting a dial tone onthe landline; detecting a busy tone on the landline; or detecting a ringsignal on the landline.
 6. The wireless backup telephone device of claim1, further operable for: requesting a temporary line directory numberfor use while providing the emergency backup telephone service to thecustomer premises telephone equipment; receiving the temporary linedirectory number; and transmitting the temporary line directory numberto the telephone call redirection device.
 7. The wireless backuptelephone device of claim 1, further operable for: in response topowering on the wireless communication device, activating a telephonebackup indication device in an alarm system located in the customerpremises.
 8. The wireless backup telephone device of claim 1, furtheroperable for: in response to powering down the wireless communicationdevice, deactivating a telephone backup indication device in an alarmsystem located in the customer premises.
 9. The wireless backuptelephone device of claim 1, further operable for: in response topowering on the wireless communication device, informing a maintenancecenter of the landline telephone service.
 10. The wireless backuptelephone device of claim 1, further operable for: charging a batterywithin the wireless communication device.
 11. The wireless backuptelephone device of claim 1, wherein the wireless communication Deviceis removable from a socket attached to the wireless backup telephonedevice.
 12. The wireless backup telephone device of claim 1, furtheroperable for detecting the interruption of telephone service provided bythe landline to the customer premises telephone equipment by detecting aloss of voltage in the landline.
 13. The wireless backup telephonedevice of claim 1, further operable for detecting the interruption oftelephone service provided by the landline to the customer premisestelephone equipment by detecting a loss of dial tone on the landline.14. The wireless backup telephone device of claim 1, further operablefor detecting the interruption of telephone service provided by thelandline to the customer premises telephone equipment by detecting aloss of ring voltage in the landline.
 15. The wireless backup telephonedevice of claim 1, further operable for detecting the interruption oftelephone service provided by the landline to the customer premisestelephone equipment by detecting a loss of current in the landline. 16.The wireless backup telephone device of claim 1, further operable fordetecting the interruption of telephone service provided by the landlineto the customer premises telephone equipment by monitoring a telephonecall taking place on the landline and detecting a lack of progress inthe telephone call.
 17. The device of claim 1, wherein providingemergency backup telephone service includes sending data to the customerpremises telephone equipment.
 18. The device of claim 1, whereinproviding emergency backup telephone service includes receiving datafrom the customer premises telephone equipment.
 19. The device of claim1, wherein providing emergency backup telephone service includes sendingdata to the wireless communication device.
 20. The device of claim 1,wherein providing emergency backup telephone service includes receivingdata from the wireless communication device.
 21. A premises alarm systemcomprising a wireless backup telephone device for providing emergencybackup telephone service to customer premises telephone equipmentconnected through a landline to a telephone network, the alarm systemoperable for: detecting an interruption of telephone service provided bythe landline to the customer premises telephone equipment; in responseto detecting the interruption, powering a wireless communication deviceoperable for communicating with a wireless network; switching thecustomer premises telephone equipment to be functionally connected tothe wireless communication device; transmitting a message instructing atelephone call redirection device to forward telephone calls directed toa directory number assigned to the customer premises telephone equipmentto a directory number assigned to the wireless communication device;providing emergency backup telephone service to the customer premisestelephone equipment through the wireless communication device; andnotifying the customer of the landline interruption by activating atelephone backup indication device in the premises alarm system locatedin the customer premises.
 22. The premises alarm system of claim 21further comprising a voltage generator, a ring generator, and a dialtone generator for providing emergency backup telephone service to thecustomer premises telephone equipment.
 23. The premises alarm system ofclaim 21, further operable for: detecting resumption of telephoneservice provided by the landline to the customer premises equipment;switching the customer premises equipment to be disconnected to thewireless communication device; powering down the wireless communicationdevice; and notifying the customer of the resumption in the landlinetelephone service by deactivating the telephone backup indication devicein the alarm system located in the customer premises.
 24. The premisesalarm system of claim 23, further operable for: transmitting a messageinstructing a telephone call redirection device to forward telephonecalls to the directory number assigned to the wireless communicationdevice to the directory number assigned to the customer premisestelephone equipment.
 25. The premises alarm system of claim 21, furtheroperable for: requesting a temporary line directory number for use whileproviding the emergency backup telephone service to the customerpremises telephone equipment; receiving the temporary line directorynumber; and transmitting the temporary line directory number to thetelephone call redirection device.
 26. The system of claim 21, thesystem, further operable for sending data to the customer premisestelephone equipment.
 27. The system of claim 21, the system, furtheroperable for receiving data from the customer premises telephoneequipment.
 28. The system of claim 21, the system, further operable forsending data to the wireless communication device.
 29. The system ofclaim 21, the system, further operable for receiving data from thewireless communication device.
 30. A computer program product comprisinga computer usable medium having control logic stored therein for causinga computer to support a wireless backup emergency telephone service tocustomer premises telephone equipment connected to a landline telephonenetwork, the control logic comprising: computer readable program codefor causing the computer to receive a forwarding message from a wirelesscommunication device located in a backup device; computer readableprogram code for causing the computer to execute a call forwardingroutine in response to receiving a forwarding message from a backupdevice, the call forwarding routine comprising: computer readableprogram code for causing the computer to enter a forwarding record intoa call redirection device to redirect calls to a directory number of asubscriber's landline connection to the wireless communication device ofthe backup device; and computer readable program code for causing thecomputer to forward an incoming call to the customer premises equipmentthrough the wireless network to the wireless communication device.